# OpcReadEventsHistoryRequest Members

> Reference: Represents the request of the HistoryRead service of OPC UA, which reads the history of events of nodes.

<dl class="api-definition">
<dt>Type</dt>
<dd><a href="./">OpcReadEventsHistoryRequest</a></dd>
<dt>Namespace</dt>
<dd><a href="../namespaces/opc.uafx.services">Opc.UaFx.Services</a></dd>
<dt>Assembly</dt>
<dd>Opc.UaFx.Advanced.dll</dd>
<dt>Package</dt>
<dd>Opc.UaFx.Advanced v2.59.0</dd>
<dt>Also in</dt>
<dd>Opc.UaFx.Client</dd>
</dl>

Inherits members from [OpcServiceRequest&lt;HistoryReadValueId, HistoryReadValueIdCollection&gt;](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcservicerequest-2/members), [OpcServiceRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcservicerequest/members).

## Constructors

### OpcReadEventsHistoryRequest

<span class="api-meta">4 overloads</span>

| Overload | Description |
|---|---|
| [OpcReadEventsHistoryRequest(OpcReadEventHistoryDetails, IEnumerable&lt;HistoryReadValueId&gt;)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/members#opcreadeventshistoryrequest-opc-uafx-opcreadeventhistorydetails-system-collections-generic-ienumerable-of-opc-ua-historyreadvalueid) | Initializes a new instance of the [OpcReadEventsHistoryRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/) class using the specified `details` and `commands` and a new header. |
| [OpcReadEventsHistoryRequest(OpcReadEventHistoryDetails, params HistoryReadValueId\[\])](#opcreadeventshistoryrequest-opc-uafx-opcreadeventhistorydetails-opc-ua-historyreadvalueid-array) | Initializes a new instance of the [OpcReadEventsHistoryRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/) class using the specified `details` and `commands` and a new header. |
| [OpcReadEventsHistoryRequest(IOpcServiceRequestHeader, OpcReadEventHistoryDetails, IEnumerable&lt;HistoryReadValueId&gt;)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/members#opcreadeventshistoryrequest-opc-uafx-services-iopcservicerequestheader-opc-uafx-opcreadeventhistorydetails-system-collections-generic-ienumerable-of-opc-ua-historyreadvalueid) | Initializes a new instance of the [OpcReadEventsHistoryRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/) class using the specified `header`, `details` and `commands`. |
| [OpcReadEventsHistoryRequest(IOpcServiceRequestHeader, OpcReadEventHistoryDetails, params HistoryReadValueId\[\])](#opcreadeventshistoryrequest-opc-uafx-services-iopcservicerequestheader-opc-uafx-opcreadeventhistorydetails-opc-ua-historyreadvalueid-array) | Initializes a new instance of the [OpcReadEventsHistoryRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/) class using the specified `header`, `details` and `commands`. |

#### OpcReadEventsHistoryRequest(OpcReadEventHistoryDetails, IEnumerable&lt;HistoryReadValueId&gt;)

Initializes a new instance of the [OpcReadEventsHistoryRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/) class using the specified `details` and `commands` and a new header.

<div class="api-signature" data-lang="csharp">

```csharp
public OpcReadEventsHistoryRequest(
    OpcReadEventHistoryDetails details,
    IEnumerable<HistoryReadValueId> commands)
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
<CLSCompliant(False)>
Public Sub New(
    details As OpcReadEventHistoryDetails,
    commands As IEnumerable(Of HistoryReadValueId))
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `details` | [OpcReadEventHistoryDetails](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadeventhistorydetails/) | The details which specify the events to read. |
| `commands` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;<abbr title="OPC Foundation stack type, not documented here: Opc.Ua.HistoryReadValueId">HistoryReadValueId</abbr>&gt; | The commands which specify the nodes whose event history is to be read. |

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `commands` is a null reference (Nothing in Visual Basic). |

#### OpcReadEventsHistoryRequest(OpcReadEventHistoryDetails, params HistoryReadValueId\[\])

Initializes a new instance of the [OpcReadEventsHistoryRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/) class using the specified `details` and `commands` and a new header.

<div class="api-signature" data-lang="csharp">

```csharp
public OpcReadEventsHistoryRequest(
    OpcReadEventHistoryDetails details,
    params HistoryReadValueId[] commands)
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
<CLSCompliant(False)>
Public Sub New(
    details As OpcReadEventHistoryDetails,
    ParamArray commands As HistoryReadValueId())
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `details` | [OpcReadEventHistoryDetails](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadeventhistorydetails/) | The details which specify the events to read. |
| `commands` | params <abbr title="OPC Foundation stack type, not documented here: Opc.Ua.HistoryReadValueId">HistoryReadValueId</abbr>[] | The commands which specify the nodes whose event history is to be read. |

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `commands` is a null reference (Nothing in Visual Basic). |

#### OpcReadEventsHistoryRequest(IOpcServiceRequestHeader, OpcReadEventHistoryDetails, IEnumerable&lt;HistoryReadValueId&gt;)

Initializes a new instance of the [OpcReadEventsHistoryRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/) class using the specified `header`, `details` and `commands`.

<div class="api-signature" data-lang="csharp">

```csharp
public OpcReadEventsHistoryRequest(
    IOpcServiceRequestHeader header,
    OpcReadEventHistoryDetails details,
    IEnumerable<HistoryReadValueId> commands)
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
<CLSCompliant(False)>
Public Sub New(
    header As IOpcServiceRequestHeader,
    details As OpcReadEventHistoryDetails,
    commands As IEnumerable(Of HistoryReadValueId))
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `header` | [IOpcServiceRequestHeader](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.iopcservicerequestheader/) | The header of the request. |
| `details` | [OpcReadEventHistoryDetails](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadeventhistorydetails/) | The details which specify the events to read. |
| `commands` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;<abbr title="OPC Foundation stack type, not documented here: Opc.Ua.HistoryReadValueId">HistoryReadValueId</abbr>&gt; | The commands which specify the nodes whose event history is to be read. |

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `header` or the `commands` is a null reference (Nothing in Visual Basic). |

#### OpcReadEventsHistoryRequest(IOpcServiceRequestHeader, OpcReadEventHistoryDetails, params HistoryReadValueId\[\])

Initializes a new instance of the [OpcReadEventsHistoryRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcreadeventshistoryrequest/) class using the specified `header`, `details` and `commands`.

<div class="api-signature" data-lang="csharp">

```csharp
public OpcReadEventsHistoryRequest(
    IOpcServiceRequestHeader header,
    OpcReadEventHistoryDetails details,
    params HistoryReadValueId[] commands)
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
<CLSCompliant(False)>
Public Sub New(
    header As IOpcServiceRequestHeader,
    details As OpcReadEventHistoryDetails,
    ParamArray commands As HistoryReadValueId())
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `header` | [IOpcServiceRequestHeader](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.iopcservicerequestheader/) | The header of the request. |
| `details` | [OpcReadEventHistoryDetails](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadeventhistorydetails/) | The details which specify the events to read. |
| `commands` | params <abbr title="OPC Foundation stack type, not documented here: Opc.Ua.HistoryReadValueId">HistoryReadValueId</abbr>[] | The commands which specify the nodes whose event history is to be read. |

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `header` or the `commands` is a null reference (Nothing in Visual Basic). |

## Properties

### Details

Gets the details which specify the events to read.

<div class="api-signature" data-lang="csharp">

```csharp
public OpcReadEventHistoryDetails Details { get; }
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
Public ReadOnly Property Details As OpcReadEventHistoryDetails
```

</div>

**Property value**

[OpcReadEventHistoryDetails](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadeventhistorydetails/)

The [OpcReadEventHistoryDetails](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadeventhistorydetails/) specified when the request was created.

### ReleaseContinuationPoints

Gets or sets a value indicating whether the continuation points of the commands are to be released.

<div class="api-signature" data-lang="csharp">

```csharp
public bool ReleaseContinuationPoints { get; set; }
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
Public Property ReleaseContinuationPoints As Boolean
```

</div>

**Property value**

[Boolean](https://learn.microsoft.com/dotnet/api/system.boolean)

The value true to release the continuation points without reading further events; otherwise the value false to continue reading. The default value is false.

### TimestampsToReturn

Gets or sets a value which specifies the timestamps to be returned for each requested [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute.

<div class="api-signature" data-lang="csharp">

```csharp
public OpcTimestampsToReturn TimestampsToReturn { get; set; }
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
Public Property TimestampsToReturn As OpcTimestampsToReturn
```

</div>

**Property value**

[OpcTimestampsToReturn](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctimestampstoreturn/)

One of the members defined by the [OpcTimestampsToReturn](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctimestampstoreturn/) enumeration except [Neither](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctimestampstoreturn/#neither).

**Remarks**

Using the value [Neither](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctimestampstoreturn/#neither) as the timestamps to return is not valid and results into a response with the status code [BadInvalidTimestampArgument](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badinvalidtimestampargument).