# OpcClient.ReadNodeHistory Method > Reference: Reads the historical values of the node identified by the nodeId specified using the details specified to select the values.
Type
OpcClient
Namespace
Opc.UaFx.Client
Assembly
Opc.UaFx.Advanced.dll
Package
Opc.UaFx.Advanced v2.59.0
Members
OpcClient Members
Also in
Opc.UaFx.Client
24 overloads | Overload | Description | |---|---| | [ReadNodeHistory(OpcNodeId, OpcReadHistoryDetails)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-opc-uafx-opcnodeid-opc-uafx-opcreadhistorydetails)since v2.23 | Reads the historical values of the node identified by the `nodeId` specified using the `details` specified to select the values. | | [ReadNodeHistory(int, OpcNodeId)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-int32-opc-uafx-opcnodeid) | Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, int, OpcNodeId)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-int32-opc-uafx-opcnodeid) | Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, int, OpcNodeId)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-system-int32-opc-uafx-opcnodeid) | Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, OpcNodeId)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-opc-uafx-opcnodeid) | Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified. | | [ReadNodeHistory(int, string)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-int32-system-string) | Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, int, string)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-int32-system-string) | Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, int, string)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-system-int32-system-string) | Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, string)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-system-string) | Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified. | | [ReadNodeHistory(int, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-int32-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, int, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-int32-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, int, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-system-int32-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified. | | [ReadNodeHistory(int, string, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-int32-system-string-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, int, string, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-int32-system-string-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, int, string, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-system-int32-system-string-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, string, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-system-string-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified. | | [ReadNodeHistory(int, int, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-int32-system-int32-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, int, int, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-int32-system-int32-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, int, int, int)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-system-int32-system-int32-system-int32) | Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(int, OpcReadNodeHistory)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-int32-opc-uafx-client-opcreadnodehistory) | Reads the raw historical values of the node as defined by the `command` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, int, OpcReadNodeHistory)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-int32-opc-uafx-client-opcreadnodehistory) | Reads the raw historical values of the node as defined by the `command` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, int, OpcReadNodeHistory)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-system-int32-opc-uafx-client-opcreadnodehistory) | Reads the raw historical values of the node as defined by the `command` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page. | | [ReadNodeHistory(DateTime?, DateTime?, OpcReadNodeHistory)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistory#readnodehistory-system-nullable-of-system-datetime-system-nullable-of-system-datetime-opc-uafx-client-opcreadnodehistory) | Reads the raw historical values of the node as defined by the `command` specified within the period defined by the `startTime` and `endTime` specified. | **Exceptions (all overloads)** | Exception | Condition | |---|---| | [OpcException](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcexception/) | The client is not connected to the server or the service execution failed upon different circumstances; for more details see exception details. | | [ObjectDisposedException](https://learn.microsoft.com/dotnet/api/system.objectdisposedexception) | The object has been disposed of. | ## ReadNodeHistory(OpcNodeId, OpcReadHistoryDetails) since v2.23 Reads the historical values of the node identified by the `nodeId` specified using the `details` specified to select the values.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( OpcNodeId nodeId, OpcReadHistoryDetails details) ```
```vbnet Public Function ReadNodeHistory( nodeId As OpcNodeId, details As OpcReadHistoryDetails) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `nodeId` | [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) | The [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) of the node whose history is to be read. | | `details` | [OpcReadHistoryDetails](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadhistorydetails/) | The [OpcReadHistoryDetails](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadhistorydetails/) which define the criteria to use to select the historical values. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `details` is an instance of the [OpcReadNodeHistoryModifiedDetails](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadnodehistorymodifieddetails/) class; to read modified values use [ReadNodeHistoryModified](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodehistorymodified#readnodehistorymodified-opc-uafx-opcnodeid-opc-uafx-opcreadhistorydetails). | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` or `details` is a null reference (Nothing in Visual Basic). | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(int, OpcNodeId) Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( int numberOfValues, OpcNodeId nodeId) ```
```vbnet Public Function ReadNodeHistory( numberOfValues As Integer, nodeId As OpcNodeId) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. | | `nodeId` | [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) | The [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) of the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)). | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, int, OpcNodeId) Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, int numberOfValues, OpcNodeId nodeId) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, numberOfValues As Integer, nodeId As OpcNodeId) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) | The [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) of the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` is a null reference (Nothing in Visual Basic) or equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, int, OpcNodeId) Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, DateTime? endTime, int numberOfValues, OpcNodeId nodeId) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, numberOfValues As Integer, nodeId As OpcNodeId) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified and the `numberOfValues` is equals zero the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified and the `numberOfValues` is equals zero the `startTime` needs to be specified. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) | The [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) of the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue) and `numberOfValues` is lower or equals zero. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, OpcNodeId) Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified.
```csharp public IEnumerable ReadNodeHistory( DateTime? startTime, DateTime? endTime, OpcNodeId nodeId) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, nodeId As OpcNodeId) As IEnumerable(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified the `startTime` needs to be specified. | | `nodeId` | [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) | The [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) of the node whose history is to be read. | **Returns** [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> A sequence of the [OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/) instances read for the node or an empty sequence if no values have been read for the node. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | **Remarks** All values within the period are read, also if the server provides them using multiple responses. In case there the server reports a bad status code for the node, an empty sequence is returned instead of throwing an exception. ## ReadNodeHistory(int, string) Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( int numberOfValues, string nodeId) ```
```vbnet Public Function ReadNodeHistory( numberOfValues As Integer, nodeId As String) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. | | `nodeId` | [String](https://learn.microsoft.com/dotnet/api/system.string) | The textual node identifier of the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null reference (Nothing in Visual Basic) or equals [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty), which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | | [FormatException](https://learn.microsoft.com/dotnet/api/system.formatexception) | The `nodeId` is not a valid node identifier expression (see [Parse](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#parse)) and [AlwaysParseStringIdentifiers](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcautomatism/members#alwaysparsestringidentifiers) is false. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, int, string) Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, int numberOfValues, string nodeId) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, numberOfValues As Integer, nodeId As String) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [String](https://learn.microsoft.com/dotnet/api/system.string) | The textual node identifier of the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null reference (Nothing in Visual Basic) or equals [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty), which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` is a null reference (Nothing in Visual Basic) or equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | | [FormatException](https://learn.microsoft.com/dotnet/api/system.formatexception) | The `nodeId` is not a valid node identifier expression (see [Parse](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#parse)) and [AlwaysParseStringIdentifiers](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcautomatism/members#alwaysparsestringidentifiers) is false. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, int, string) Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, DateTime? endTime, int numberOfValues, string nodeId) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, numberOfValues As Integer, nodeId As String) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified and the `numberOfValues` is equals zero the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified and the `numberOfValues` is equals zero the `startTime` needs to be specified. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [String](https://learn.microsoft.com/dotnet/api/system.string) | The textual node identifier of the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null reference (Nothing in Visual Basic) or equals [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty), which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue) and `numberOfValues` is lower or equals zero. | | [FormatException](https://learn.microsoft.com/dotnet/api/system.formatexception) | The `nodeId` is not a valid node identifier expression (see [Parse](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#parse)) and [AlwaysParseStringIdentifiers](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcautomatism/members#alwaysparsestringidentifiers) is false. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, string) Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified.
```csharp public IEnumerable ReadNodeHistory( DateTime? startTime, DateTime? endTime, string nodeId) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, nodeId As String) As IEnumerable(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified the `startTime` needs to be specified. | | `nodeId` | [String](https://learn.microsoft.com/dotnet/api/system.string) | The textual node identifier of the node whose history is to be read. | **Returns** [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> A sequence of the [OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/) instances read for the node or an empty sequence if no values have been read for the node. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null reference (Nothing in Visual Basic) or equals [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty), which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | | [FormatException](https://learn.microsoft.com/dotnet/api/system.formatexception) | The `nodeId` is not a valid node identifier expression (see [Parse](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#parse)) and [AlwaysParseStringIdentifiers](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcautomatism/members#alwaysparsestringidentifiers) is false. | **Remarks** All values within the period are read, also if the server provides them using multiple responses. In case there the server reports a bad status code for the node, an empty sequence is returned instead of throwing an exception. ## ReadNodeHistory(int, int) Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( int numberOfValues, int nodeId) ```
```vbnet Public Function ReadNodeHistory( numberOfValues As Integer, nodeId As Integer) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. | | `nodeId` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The numeric node identifier of the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is equals zero, which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, int, int) Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, int numberOfValues, int nodeId) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, numberOfValues As Integer, nodeId As Integer) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The numeric node identifier of the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is equals zero, which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` is a null reference (Nothing in Visual Basic) or equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, int, int) Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, DateTime? endTime, int numberOfValues, int nodeId) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, numberOfValues As Integer, nodeId As Integer) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified and the `numberOfValues` is equals zero the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified and the `numberOfValues` is equals zero the `startTime` needs to be specified. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The numeric node identifier of the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is equals zero, which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue) and `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, int) Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified.
```csharp public IEnumerable ReadNodeHistory( DateTime? startTime, DateTime? endTime, int nodeId) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, nodeId As Integer) As IEnumerable(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified the `startTime` needs to be specified. | | `nodeId` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The numeric node identifier of the node whose history is to be read. | **Returns** [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> A sequence of the [OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/) instances read for the node or an empty sequence if no values have been read for the node. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is equals zero, which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | **Remarks** All values within the period are read, also if the server provides them using multiple responses. In case there the server reports a bad status code for the node, an empty sequence is returned instead of throwing an exception. ## ReadNodeHistory(int, string, int) Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( int numberOfValues, string nodeId, int namespaceIndex) ```
```vbnet Public Function ReadNodeHistory( numberOfValues As Integer, nodeId As String, namespaceIndex As Integer) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. | | `nodeId` | [String](https://learn.microsoft.com/dotnet/api/system.string) | The textual node identifier of the node whose history is to be read. | | `namespaceIndex` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The index of the namespace within that the node with the `nodeId` specified can be located. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null reference (Nothing in Visual Basic) or equals [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty), which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, int, string, int) Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, int numberOfValues, string nodeId, int namespaceIndex) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, numberOfValues As Integer, nodeId As String, namespaceIndex As Integer) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [String](https://learn.microsoft.com/dotnet/api/system.string) | The textual node identifier of the node whose history is to be read. | | `namespaceIndex` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The index of the namespace within that the node with the `nodeId` specified can be located. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null reference (Nothing in Visual Basic) or equals [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty), which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` is a null reference (Nothing in Visual Basic) or equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, int, string, int) Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, DateTime? endTime, int numberOfValues, string nodeId, int namespaceIndex) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, numberOfValues As Integer, nodeId As String, namespaceIndex As Integer) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified and the `numberOfValues` is equals zero the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified and the `numberOfValues` is equals zero the `startTime` needs to be specified. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [String](https://learn.microsoft.com/dotnet/api/system.string) | The textual node identifier of the node whose history is to be read. | | `namespaceIndex` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The index of the namespace within that the node with the `nodeId` specified can be located. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null reference (Nothing in Visual Basic) or equals [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty), which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue) and `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, string, int) Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified.
```csharp public IEnumerable ReadNodeHistory( DateTime? startTime, DateTime? endTime, string nodeId, int namespaceIndex) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, nodeId As String, namespaceIndex As Integer) As IEnumerable(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified the `startTime` needs to be specified. | | `nodeId` | [String](https://learn.microsoft.com/dotnet/api/system.string) | The textual node identifier of the node whose history is to be read. | | `namespaceIndex` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The index of the namespace within that the node with the `nodeId` specified can be located. | **Returns** [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> A sequence of the [OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/) instances read for the node or an empty sequence if no values have been read for the node. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is a null reference (Nothing in Visual Basic) or equals [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty), which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | **Remarks** All values within the period are read, also if the server provides them using multiple responses. In case there the server reports a bad status code for the node, an empty sequence is returned instead of throwing an exception. ## ReadNodeHistory(int, int, int) Reads the raw historical values of the node identified by the `nodeId` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( int numberOfValues, int nodeId, int namespaceIndex) ```
```vbnet Public Function ReadNodeHistory( numberOfValues As Integer, nodeId As Integer, namespaceIndex As Integer) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. | | `nodeId` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The numeric node identifier of the node whose history is to be read. | | `namespaceIndex` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The index of the namespace within that the node with the `nodeId` specified can be located. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is equals zero, which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, int, int, int) Reads the raw historical values of the node identified by the `nodeId` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, int numberOfValues, int nodeId, int namespaceIndex) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, numberOfValues As Integer, nodeId As Integer, namespaceIndex As Integer) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The numeric node identifier of the node whose history is to be read. | | `namespaceIndex` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The index of the namespace within that the node with the `nodeId` specified can be located. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is equals zero, which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` is a null reference (Nothing in Visual Basic) or equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, int, int, int) Reads the raw historical values of the node identified by the `nodeId` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, DateTime? endTime, int numberOfValues, int nodeId, int namespaceIndex) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, numberOfValues As Integer, nodeId As Integer, namespaceIndex As Integer) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified and the `numberOfValues` is equals zero the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified and the `numberOfValues` is equals zero the `startTime` needs to be specified. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `nodeId` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The numeric node identifier of the node whose history is to be read. | | `namespaceIndex` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The index of the namespace within that the node with the `nodeId` specified can be located. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is equals zero, which results in a null identifier (see [IsNull](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/members#isnull)) or the `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue) and `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(int, OpcReadNodeHistory) Reads the raw historical values of the node as defined by the `command` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( int numberOfValues, OpcReadNodeHistory command) ```
```vbnet Public Function ReadNodeHistory( numberOfValues As Integer, command As OpcReadNodeHistory) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. | | `command` | [OpcReadNodeHistory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcreadnodehistory/) | The [OpcReadNodeHistory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcreadnodehistory/) command which defines the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `command` is a null reference (Nothing in Visual Basic). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, int, OpcReadNodeHistory) Reads the raw historical values of the node as defined by the `command` specified beginning at the `startTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, int numberOfValues, OpcReadNodeHistory command) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, numberOfValues As Integer, command As OpcReadNodeHistory) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `command` | [OpcReadNodeHistory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcreadnodehistory/) | The [OpcReadNodeHistory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcreadnodehistory/) command which defines the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `startTime` is a null reference (Nothing in Visual Basic) or equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `command` is a null reference (Nothing in Visual Basic). | | [ArgumentOutOfRangeException](https://learn.microsoft.com/dotnet/api/system.argumentoutofrangeexception) | The `numberOfValues` is lower or equals zero. | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, int, OpcReadNodeHistory) Reads the raw historical values of the node as defined by the `command` specified within the period defined by the `startTime` and `endTime` specified page by page using the `numberOfValues` specified as the maximum number of values per page.
```csharp public IOpcNodeHistoryNavigator ReadNodeHistory( DateTime? startTime, DateTime? endTime, int numberOfValues, OpcReadNodeHistory command) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, numberOfValues As Integer, command As OpcReadNodeHistory) As IOpcNodeHistoryNavigator(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified and the `numberOfValues` is equals zero the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified and the `numberOfValues` is equals zero the `startTime` needs to be specified. | | `numberOfValues` | [Int32](https://learn.microsoft.com/dotnet/api/system.int32) | The maximum number of values returned for the node per page. If only one time is specified, the time range shall extend to return this number of values. | | `command` | [OpcReadNodeHistory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcreadnodehistory/) | The [OpcReadNodeHistory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcreadnodehistory/) command which defines the node whose history is to be read. | **Returns** [IOpcNodeHistoryNavigator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> An instance implementing the [IOpcNodeHistoryNavigator<T>](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/) interface which provides the first page of the historical values read for the node and further pages using its [MoveNextPage](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.iopcnodehistorynavigator-1/members#movenextpage) method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue) and `numberOfValues` is lower or equals zero. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `command` is a null reference (Nothing in Visual Basic). | **Remarks** In case there the server reports a bad status code for the node, the navigator provides no values instead of throwing an exception. ## ReadNodeHistory(DateTime?, DateTime?, OpcReadNodeHistory) Reads the raw historical values of the node as defined by the `command` specified within the period defined by the `startTime` and `endTime` specified.
```csharp public IEnumerable ReadNodeHistory( DateTime? startTime, DateTime? endTime, OpcReadNodeHistory command) ```
```vbnet Public Function ReadNodeHistory( startTime As Date?, endTime As Date?, command As OpcReadNodeHistory) As IEnumerable(Of OpcHistoryValue) ```
**Parameters** | Name | Type | Description | |---|---|---| | `startTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The beginning of the period to read or a null reference (Nothing in Visual Basic) if no specific start time is specified. If `startTime` is not specified the `endTime` needs to be specified. | | `endTime` | [Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)<[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)> | The end of the period to read or a null reference (Nothing in Visual Basic) if no specific end time is specified. If `endTime` is not specified the `startTime` needs to be specified. | | `command` | [OpcReadNodeHistory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcreadnodehistory/) | The [OpcReadNodeHistory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcreadnodehistory/) command which defines the node whose history is to be read. | **Returns** [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)<[OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/)> A sequence of the [OpcHistoryValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opchistoryvalue/) instances read for the node or an empty sequence if no values have been read for the node. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `startTime` and `endTime` are a null reference (Nothing in Visual Basic) or are equals [MinValue](https://learn.microsoft.com/dotnet/api/system.datetime.minvalue). | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `command` is a null reference (Nothing in Visual Basic). | **Remarks** All values within the period are read, also if the server provides them using multiple responses. In case there the server reports a bad status code for the node, an empty sequence is returned instead of throwing an exception.