# OpcSubscriptionSetup Members > Reference: Defines a set of properties which can be used to create a whole OpcSubscription including its OpcMonitoredItem objects.
Type
OpcSubscriptionSetup
Namespace
Opc.UaFx.Client
Assembly
Opc.UaFx.Advanced.dll
Package
Opc.UaFx.Advanced v2.59.0
Also in
Opc.UaFx.Client
## Constructors ### OpcSubscriptionSetup 3 overloads | Overload | Description | |---|---| | [OpcSubscriptionSetup()](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#opcsubscriptionsetup-noparams) | Initializes a new instance of the [OpcSubscriptionSetup](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/) class. | | [OpcSubscriptionSetup(IEnumerable<OpcMonitoredItem>)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#opcsubscriptionsetup-system-collections-generic-ienumerable-of-opc-uafx-client-opcmonitoreditem) | Initializes a new instance of the [OpcSubscriptionSetup](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/) class using the sequence of `monitoredItems`. | | [OpcSubscriptionSetup(params OpcMonitoredItem\[\])](#opcsubscriptionsetup-opc-uafx-client-opcmonitoreditem-array) | Initializes a new instance of the [OpcSubscriptionSetup](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/) class using the sequence of `monitoredItems`. | #### OpcSubscriptionSetup() Initializes a new instance of the [OpcSubscriptionSetup](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/) class.
```csharp public OpcSubscriptionSetup() ```
```vbnet Public Sub New() ```
#### OpcSubscriptionSetup(IEnumerable<OpcMonitoredItem>) Initializes a new instance of the [OpcSubscriptionSetup](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/) class using the sequence of `monitoredItems`.
```csharp public OpcSubscriptionSetup(IEnumerable monitoredItems) ```
```vbnet Public Sub New(monitoredItems As IEnumerable(Of OpcMonitoredItem)) ```
**Parameters** | Name | Type | Description | |---|---|---| | `monitoredItems` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)<[OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/)> | A sequence of [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) objects. | **Exceptions** | Exception | Condition | |---|---| | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `monitoredItems` is a null reference (Nothing in Visual Basic). | #### OpcSubscriptionSetup(params OpcMonitoredItem\[\]) Initializes a new instance of the [OpcSubscriptionSetup](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/) class using the sequence of `monitoredItems`.
```csharp public OpcSubscriptionSetup(params OpcMonitoredItem[] monitoredItems) ```
```vbnet Public Sub New(ParamArray monitoredItems As OpcMonitoredItem()) ```
**Parameters** | Name | Type | Description | |---|---|---| | `monitoredItems` | params [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/)[] | An array of [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) objects. | **Exceptions** | Exception | Condition | |---|---| | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `monitoredItems` is a null reference (Nothing in Visual Basic). | ## Properties ### Changed Occurs then a monitored is added, modified, deleted or changes on the [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) were applied.
```csharp public OpcSubscriptionChangedEventHandler Changed { get; set; } ```
```vbnet Public Property Changed As OpcSubscriptionChangedEventHandler ```
**Property value** [OpcSubscriptionChangedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionchangedeventhandler/) ### DataChangeReceived Occurs then a monitored item receives an event notification which is not handled by an [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) on its [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#datachangereceived) event.
```csharp public OpcDataChangeReceivedEventHandler DataChangeReceived { get; set; } ```
```vbnet Public Property DataChangeReceived As OpcDataChangeReceivedEventHandler ```
**Property value** [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) **Remarks** This event only occurs if an event notification is not handled by the according [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#datachangereceived) event handler. ### DisplayName Gets or sets the name of the [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) used just for display purpose in the client application.
```csharp public string DisplayName { get; set; } ```
```vbnet Public Property DisplayName As String ```
**Property value** [String](https://learn.microsoft.com/dotnet/api/system.string) The name of the [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) used just for display purpose in the client application. ### EventReceived Occurs then a monitored item receives an event notification which is not handled by an [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) on its [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#eventreceived) event.
```csharp public OpcEventReceivedEventHandler EventReceived { get; set; } ```
```vbnet Public Property EventReceived As OpcEventReceivedEventHandler ```
**Property value** [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) **Remarks** This event only occurs if an event notification is not handled by the according [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#eventreceived) event handler. ### KeepAliveCount Gets or sets a value which defines the requested number of times the publishing timer have to expire without any notification being sent before the server have to send a keep-alive message to the client.
```csharp public long KeepAliveCount { get; set; } ```
```vbnet Public Property KeepAliveCount As Long ```
**Property value** [Int64](https://learn.microsoft.com/dotnet/api/system.int64) A value of zero indicates that the server have to revise the smallest supported keep-alive count. The default value of this property is 10. The value of this property configures the keep-alive counter that counts the number of consecutive publishing cycles in which there have been no notifications to report to the client. When the maximum keep-alive count is reached, a publish request is de-queued and used to return a keep-alive message. This keep-alive message informs the client that the subscription is still active. The maximum keep-alive count may be subsequently modified. If there are no publish requests queued, the server waits for the next one to be received and sends the keep-alive immediately without waiting for the next publishing cycle. The value of the underlying property is an [uint](https://learn.microsoft.com/dotnet/api/system.uint32) which is covered using a [long](https://learn.microsoft.com/dotnet/api/system.int64) to assure CLS compliance. In fact this restricts the value range of this property to [MinValue](https://learn.microsoft.com/dotnet/api/system.uint32.minvalue) and [MaxValue](https://learn.microsoft.com/dotnet/api/system.uint32.maxvalue). ### LifetimeCount Gets or sets a value which defines the requested number of times the publishing timer have to expire without any publish request before the server have to delete this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public long LifetimeCount { get; set; } ```
```vbnet Public Property LifetimeCount As Long ```
**Property value** [Int64](https://learn.microsoft.com/dotnet/api/system.int64) The number of times the publishing timer have to expire without any publish request. A recommended value is at least a minimum of three times of the [KeepAliveCount](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#keepalivecount). The default value of this property is 100. **Remarks** The value of the underlying property is an [uint](https://learn.microsoft.com/dotnet/api/system.uint32) which is covered using a [long](https://learn.microsoft.com/dotnet/api/system.int64) to assure CLS compliance. In fact this restricts the value range of this property to [MinValue](https://learn.microsoft.com/dotnet/api/system.uint32.minvalue) and [MaxValue](https://learn.microsoft.com/dotnet/api/system.uint32.maxvalue). ### MaxMessageCount Gets or sets the maximum number of notifications to keep in the cache.
```csharp public int MaxMessageCount { get; set; } ```
```vbnet Public Property MaxMessageCount As Integer ```
**Property value** [Int32](https://learn.microsoft.com/dotnet/api/system.int32) The maximum number of notification to keep in the cache. The default value of this property is 10. ### MaxNotificationsPerPublish Gets or sets a value which defines the maximum number of notifications that the client wants to receive in a single publish response.
```csharp public long MaxNotificationsPerPublish { get; set; } ```
```vbnet Public Property MaxNotificationsPerPublish As Long ```
**Property value** [Int64](https://learn.microsoft.com/dotnet/api/system.int64) The maximum number of notifications that the client wants to receive in a single publish response. The number of notifications per publish is the sum of [MonitoredItems](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#monitoreditems) in a data change related notification and the number of events in an event notification. The default value of this property is 1000. **Remarks** A value of zero indicates that there is no limit. The value of the underlying property is an [uint](https://learn.microsoft.com/dotnet/api/system.uint32) which is covered using a [long](https://learn.microsoft.com/dotnet/api/system.int64) to assure CLS compliance. In fact this restricts the value range of this property to [MinValue](https://learn.microsoft.com/dotnet/api/system.uint32.minvalue) and [MaxValue](https://learn.microsoft.com/dotnet/api/system.uint32.maxvalue). ### MinLifetimeInterval Gets or sets a value which defines the minimum lifetime interval to apply in respect of the [PublishingInterval](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#publishinginterval) and the [LifetimeCount](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#lifetimecount) configured.
```csharp public long MinLifetimeInterval { get; set; } ```
```vbnet Public Property MinLifetimeInterval As Long ```
**Property value** [Int64](https://learn.microsoft.com/dotnet/api/system.int64) The interval which should be a multiple of the [PublishingInterval](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#publishinginterval) to assure that the [LifetimeCount](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#lifetimecount) requested is sensible enough to get covered within the [PublishingInterval](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#publishinginterval). ### MonitoredItems Gets a read-only collection of [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) instances associated with this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public OpcMonitoredItemReadOnlyCollection MonitoredItems { get; } ```
```vbnet Public ReadOnly Property MonitoredItems As OpcMonitoredItemReadOnlyCollection ```
**Property value** [OpcMonitoredItemReadOnlyCollection](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditemreadonlycollection/) An instance of the [OpcMonitoredItemReadOnlyCollection](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditemreadonlycollection/) class. **Remarks** Use the monitored item related methods of this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) to manipulate the items contained in the collection offered by this property. ### NotificationFailed since v2.57 Occurs then a notification message for the [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) failed to be received, so that its data changes and events do not reach the monitored items.
```csharp public OpcNotificationFailedEventHandler NotificationFailed { get; set; } ```
```vbnet Public Property NotificationFailed As OpcNotificationFailedEventHandler ```
**Property value** [OpcNotificationFailedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcnotificationfailedeventhandler/) **Remarks** The session requests a failed message again from the server until the server no longer holds it. This event occurs once for each message, however often it fails, and once more with [BadMessageNotAvailable](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badmessagenotavailable) when the message is lost. An event which is not handled by this event handler is passed to the [NotificationFailed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/notificationfailed) event of the [OpcClient](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/) which owns the [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/). ### NotificationReceived Occurs then a [OpcNotification](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnotification/) for this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) has been received by the session which owns this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public OpcNotificationReceivedEventHandler NotificationReceived { get; set; } ```
```vbnet Public Property NotificationReceived As OpcNotificationReceivedEventHandler ```
**Property value** [OpcNotificationReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcnotificationreceivedeventhandler/) ### Priority Gets or sets a value which defines the relative priority of the subscription used to priorize notifications being send then more than one subscription is to be notified.
```csharp public int Priority { get; set; } ```
```vbnet Public Property Priority As Integer ```
**Property value** [Int32](https://learn.microsoft.com/dotnet/api/system.int32) The relative priority of the subscription to notify. **Remarks** In case of subscriptions with equal priority the server shall send the notifications in a round-robin fashion. A client that does not require special priority settings should set this value to zero. The value of the underlying property is a [byte](https://learn.microsoft.com/dotnet/api/system.byte) which is covered using an [int](https://learn.microsoft.com/dotnet/api/system.int32) to assure an even API level. In fact this restricts the value range of this property to [MinValue](https://learn.microsoft.com/dotnet/api/system.byte.minvalue) and [MaxValue](https://learn.microsoft.com/dotnet/api/system.byte.maxvalue). ### PublishingInterval Gets or sets the requested number of milliseconds of the interval within the server have to send cyclic notifications to the client.
```csharp public int PublishingInterval { get; set; } ```
```vbnet Public Property PublishingInterval As Integer ```
**Property value** [Int32](https://learn.microsoft.com/dotnet/api/system.int32) The interval within the server have to send cyclic notifications to the client. A value of zero or negative indicates that the server have to revise the fastest supported publishing interval. **Remarks** The publishing interval of a subscription defines the cyclic rate at which the subscription executes. Each time it executes, it attempts to send a message to the client. Messages contain notifications that have not yet been reported to client. The negotiated value of this property is used as the default sampling interval for the [MonitoredItems](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#monitoreditems) assigned to this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/). ### PublishingIsEnabled Gets or sets a value indicating whether publishing is enabled for this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public bool PublishingIsEnabled { get; set; } ```
```vbnet Public Property PublishingIsEnabled As Boolean ```
**Property value** [Boolean](https://learn.microsoft.com/dotnet/api/system.boolean) The value true if publishing is enabled for this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/); otherwise the value false. The default value of this property is true. **Remarks** The value of this property does not affect the value of the monitoring mode property of the [MonitoredItems](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#monitoreditems). ### ReceivedDataChangeCallback Gets or sets the callback used to process data changes of the monitored items associated with this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public OpcDataChangeReceivedCallback ReceivedDataChangeCallback { get; set; } ```
```vbnet Public Property ReceivedDataChangeCallback As OpcDataChangeReceivedCallback ```
**Property value** [OpcDataChangeReceivedCallback](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedcallback/) A [OpcDataChangeReceivedCallback](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedcallback/) used to process data change items. The value can also be a null reference (Nothing in Visual Basic). **Remarks** Use this property to directly handle all data change items without to rely on the chain of registered event handlers. ### ReceivedEventCallback Gets or sets the callback used to process events of the monitored items associated with this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public OpcEventReceivedCallback ReceivedEventCallback { get; set; } ```
```vbnet Public Property ReceivedEventCallback As OpcEventReceivedCallback ```
**Property value** [OpcEventReceivedCallback](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedcallback/) A [OpcDataChangeReceivedCallback](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedcallback/) used to process event items. The value can also be a null reference (Nothing in Visual Basic). **Remarks** Use this property to directly handle all event items without to rely on the chain of registered event handlers. ### TimestampsToReturn Gets or sets the timestamps the server shall transmit for each monitored item.
```csharp public OpcTimestampsToReturn TimestampsToReturn { get; set; } ```
```vbnet Public Property TimestampsToReturn As OpcTimestampsToReturn ```
**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. The default value of this property is [Both](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctimestampstoreturn/#both). **Remarks** The "timestamps to return" criteria is only applied to [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances. This means that in case of monitoring events only event fields of the type [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) are effected by the value of this property. ### UseMonitoredItemDataCache Gets or sets a value indicating whether this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) shall forward notifications received from the server to monitored item individual caches. This enables the monitored items to process the data changes and event fields on their own.
```csharp public bool UseMonitoredItemDataCache { get; set; } ```
```vbnet Public Property UseMonitoredItemDataCache As Boolean ```
**Property value** [Boolean](https://learn.microsoft.com/dotnet/api/system.boolean) The value true if the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) instances associated with this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) receive their own item-related notification and can process the notification data on their own; otherwise the value false. The default value of this property is true. ## Methods ### AddMonitoredItem 15 overloads | Overload | Description | |---|---| | [AddMonitoredItem(OpcMonitoredItem)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-client-opcmonitoreditem) | Adds the monitored item specified by `item` to this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/). | | [AddMonitoredItem(OpcNodeId)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid) | Adds a new monitored item which subscribes to changes on the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the node specified by `nodeId`. | | [AddMonitoredItem(OpcNodeId, OpcDataChangeReceivedEventHandler)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-client-opcdatachangereceivedeventhandler) | Adds a new monitored item which subscribes to changes on the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the node specified by `nodeId`. | | [AddMonitoredItem(OpcNodeId, OpcEventReceivedEventHandler)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-client-opceventreceivedeventhandler) | Adds a new monitored item which subscribes to events on the [EventNotifier](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#eventnotifier) attribute of the node specified by `nodeId`. | | [AddMonitoredItem(OpcNodeId, OpcAttribute)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-opcattribute) | Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId`. | | [AddMonitoredItem(OpcNodeId, OpcAttribute, OpcDataChangeReceivedEventHandler)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-opcattribute-opc-uafx-client-opcdatachangereceivedeventhandler) | Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId`. | | [AddMonitoredItem(OpcNodeId, OpcAttribute, OpcEventReceivedEventHandler)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-opcattribute-opc-uafx-client-opceventreceivedeventhandler) | Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId`. | | [AddMonitoredItem(OpcNodeId, OpcMonitoringFilter)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-opcmonitoringfilter) | Adds a new monitored item which subscribes to changes on the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the node specified by `nodeId` using the further configured `filter`. | | [AddMonitoredItem(OpcNodeId, OpcDataChangeFilter, OpcDataChangeReceivedEventHandler)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-opcdatachangefilter-opc-uafx-client-opcdatachangereceivedeventhandler) | Adds a new monitored item which subscribes to changes on the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the node specified by `nodeId` using the further configured `filter`. | | [AddMonitoredItem(OpcNodeId, OpcEventFilter, OpcEventReceivedEventHandler)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-opceventfilter-opc-uafx-client-opceventreceivedeventhandler) | Adds a new monitored item which subscribes to changes on the [EventNotifier](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#eventnotifier) attribute of the node specified by `nodeId` using the further configured `filter`. | | [AddMonitoredItem(OpcNodeId, OpcAttribute, OpcMonitoringFilter)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-opcattribute-opc-uafx-opcmonitoringfilter) | Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId` using the further configured `filter`. | | [AddMonitoredItem(OpcNodeId, OpcAttribute, OpcDataChangeFilter, OpcDataChangeReceivedEventHandler)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-opcattribute-opc-uafx-opcdatachangefilter-opc-uafx-client-opcdatachangereceivedeventhandler) | Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId` using the further configured `filter`. | | [AddMonitoredItem(OpcNodeId, OpcAttribute, OpcEventFilter, OpcEventReceivedEventHandler)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-opc-uafx-opcnodeid-opc-uafx-opcattribute-opc-uafx-opceventfilter-opc-uafx-client-opceventreceivedeventhandler) | Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId` using the further configured `filter`. | | [AddMonitoredItem(IEnumerable<OpcMonitoredItem>)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#addmonitoreditem-system-collections-generic-ienumerable-of-opc-uafx-client-opcmonitoreditem) | Adds the monitored items specified by `items` to this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/). | | [AddMonitoredItem(params OpcMonitoredItem\[\])](#addmonitoreditem-opc-uafx-client-opcmonitoreditem-array) | Adds the monitored items specified by `items` to this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/). | #### AddMonitoredItem(OpcMonitoredItem) Adds the monitored item specified by `item` to this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public void AddMonitoredItem(OpcMonitoredItem item) ```
```vbnet Public Sub AddMonitoredItem(item As OpcMonitoredItem) ```
**Parameters** | Name | Type | Description | |---|---|---| | `item` | [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) | The [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) to add. | **Exceptions** | Exception | Condition | |---|---| | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `item` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId) Adds a new monitored item which subscribes to changes on the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the node specified by `nodeId`.
```csharp public OpcMonitoredItem AddMonitoredItem(OpcNodeId nodeId) ```
```vbnet Public Function AddMonitoredItem(nodeId As OpcNodeId) As OpcMonitoredItem ```
**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 its [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute is to be monitored. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcDataChangeReceivedEventHandler) Adds a new monitored item which subscribes to changes on the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the node specified by `nodeId`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcDataChangeReceivedEventHandler received) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, received As OpcDataChangeReceivedEventHandler) As OpcMonitoredItem ```
**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 its [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute is to be monitored. | | `received` | [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) | The [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) method to assign as the event handler of the [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#datachangereceived) event or a null reference (Nothing in Visual Basic) if there no event handler is to be assigned first. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcEventReceivedEventHandler) Adds a new monitored item which subscribes to events on the [EventNotifier](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#eventnotifier) attribute of the node specified by `nodeId`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcEventReceivedEventHandler received) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, received As OpcEventReceivedEventHandler) As OpcMonitoredItem ```
**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 its [EventNotifier](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#eventnotifier) attribute is to be monitored. | | `received` | [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) | The [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) method to assign as the event handler of the [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#eventreceived) event or a null reference (Nothing in Visual Basic) if there no event handler is to be assigned first. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcAttribute) Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcAttribute attribute) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, attribute As OpcAttribute) As OpcMonitoredItem ```
**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 its `attribute` is to be monitored. | | `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | The [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) to monitor. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcAttribute, OpcDataChangeReceivedEventHandler) Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcAttribute attribute, OpcDataChangeReceivedEventHandler received) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, attribute As OpcAttribute, received As OpcDataChangeReceivedEventHandler) As OpcMonitoredItem ```
**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 its `attribute` is to be monitored. | | `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | The [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) to monitor. | | `received` | [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) | The [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) method to assign as the event handler of the [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#datachangereceived) event or a null reference (Nothing in Visual Basic) if there no event handler is to be assigned first. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcAttribute, OpcEventReceivedEventHandler) Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcAttribute attribute, OpcEventReceivedEventHandler received) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, attribute As OpcAttribute, received As OpcEventReceivedEventHandler) As OpcMonitoredItem ```
**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 its `attribute` is to be monitored. | | `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | The [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) to monitor. | | `received` | [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) | The [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) method to assign as the event handler of the [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#eventreceived) event or a null reference (Nothing in Visual Basic) if there no event handler is to be assigned first. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcMonitoringFilter) Adds a new monitored item which subscribes to changes on the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the node specified by `nodeId` using the further configured `filter`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcMonitoringFilter filter) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, filter As OpcMonitoringFilter) As OpcMonitoredItem ```
**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 its [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute is to be monitored. | | `filter` | [OpcMonitoringFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcmonitoringfilter/) | The [OpcMonitoringFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcmonitoringfilter/) (either a [OpcDataChangeFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatachangefilter/) or a [OpcEventFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventfilter/)) to use to apply different conditions while monitoring the attribute. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcDataChangeFilter, OpcDataChangeReceivedEventHandler) Adds a new monitored item which subscribes to changes on the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the node specified by `nodeId` using the further configured `filter`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcDataChangeFilter filter, OpcDataChangeReceivedEventHandler received) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, filter As OpcDataChangeFilter, received As OpcDataChangeReceivedEventHandler) As OpcMonitoredItem ```
**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 its [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute is to be monitored. | | `filter` | [OpcDataChangeFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatachangefilter/) | The [OpcDataChangeFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatachangefilter/) to use to apply different conditions while monitoring the attribute. | | `received` | [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) | The [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) method to assign as the event handler of the [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#datachangereceived) event or a null reference (Nothing in Visual Basic) if there no event handler is to be assigned first. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcEventFilter, OpcEventReceivedEventHandler) Adds a new monitored item which subscribes to changes on the [EventNotifier](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#eventnotifier) attribute of the node specified by `nodeId` using the further configured `filter`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcEventFilter filter, OpcEventReceivedEventHandler received) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, filter As OpcEventFilter, received As OpcEventReceivedEventHandler) As OpcMonitoredItem ```
**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 its [EventNotifier](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#eventnotifier) attribute is to be monitored. | | `filter` | [OpcEventFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventfilter/) | The [OpcEventFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventfilter/) to use to apply different conditions while monitoring the attribute. | | `received` | [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) | The [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) method to assign as the event handler of the [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#eventreceived) event or a null reference (Nothing in Visual Basic) if there no event handler is to be assigned first. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcAttribute, OpcMonitoringFilter) Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId` using the further configured `filter`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcAttribute attribute, OpcMonitoringFilter filter) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, attribute As OpcAttribute, filter As OpcMonitoringFilter) As OpcMonitoredItem ```
**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 its `attribute` is to be monitored. | | `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | The [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) to monitor. | | `filter` | [OpcMonitoringFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcmonitoringfilter/) | The [OpcMonitoringFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcmonitoringfilter/) (either a [OpcDataChangeFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatachangefilter/) or a [OpcEventFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventfilter/)) to use to apply different conditions while monitoring the attribute. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcAttribute, OpcDataChangeFilter, OpcDataChangeReceivedEventHandler) Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId` using the further configured `filter`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcAttribute attribute, OpcDataChangeFilter filter, OpcDataChangeReceivedEventHandler received) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, attribute As OpcAttribute, filter As OpcDataChangeFilter, received As OpcDataChangeReceivedEventHandler) As OpcMonitoredItem ```
**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 its `attribute` is to be monitored. | | `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | The [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) to monitor. | | `filter` | [OpcDataChangeFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatachangefilter/) | The [OpcDataChangeFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatachangefilter/) to use to apply different conditions while monitoring the attribute. | | `received` | [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) | The [OpcDataChangeReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcdatachangereceivedeventhandler/) method to assign as the event handler of the [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#datachangereceived) event or a null reference (Nothing in Visual Basic) if there no event handler is to be assigned first. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(OpcNodeId, OpcAttribute, OpcEventFilter, OpcEventReceivedEventHandler) Adds a new monitored item which subscribes to the `attribute` of the node specified by `nodeId` using the further configured `filter`.
```csharp public OpcMonitoredItem AddMonitoredItem( OpcNodeId nodeId, OpcAttribute attribute, OpcEventFilter filter, OpcEventReceivedEventHandler received) ```
```vbnet Public Function AddMonitoredItem( nodeId As OpcNodeId, attribute As OpcAttribute, filter As OpcEventFilter, received As OpcEventReceivedEventHandler) As OpcMonitoredItem ```
**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 its `attribute` is to be monitored. | | `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | The [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) to monitor. | | `filter` | [OpcEventFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventfilter/) | The [OpcEventFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventfilter/) to use to apply different conditions while monitoring the attribute. | | `received` | [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) | The [OpcEventReceivedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventhandler/) method to assign as the event handler of the [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#eventreceived) event or a null reference (Nothing in Visual Basic) if there no event handler is to be assigned first. | **Returns** [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) A new instance of the [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) class setup with the information specified. The monitored item will then monitor the node identified by the values passed to this method. **Exceptions** | Exception | Condition | |---|---| | [ArgumentException](https://learn.microsoft.com/dotnet/api/system.argumentexception) | The `nodeId` is empty. | | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeId` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(IEnumerable<OpcMonitoredItem>) Adds the monitored items specified by `items` to this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public void AddMonitoredItem(IEnumerable items) ```
```vbnet Public Sub AddMonitoredItem(items As IEnumerable(Of OpcMonitoredItem)) ```
**Parameters** | Name | Type | Description | |---|---|---| | `items` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)<[OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/)> | A sequence of [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) istances to add. | **Exceptions** | Exception | Condition | |---|---| | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `items` is a null reference (Nothing in Visual Basic). | #### AddMonitoredItem(params OpcMonitoredItem\[\]) Adds the monitored items specified by `items` to this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public void AddMonitoredItem(params OpcMonitoredItem[] items) ```
```vbnet Public Sub AddMonitoredItem(ParamArray items As OpcMonitoredItem()) ```
**Parameters** | Name | Type | Description | |---|---|---| | `items` | params [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/)[] | An array of [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) istances to add. | **Exceptions** | Exception | Condition | |---|---| | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `items` is a null reference (Nothing in Visual Basic). | ### RemoveMonitoredItem 3 overloads | Overload | Description | |---|---| | [RemoveMonitoredItem(OpcMonitoredItem)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#removemonitoreditem-opc-uafx-client-opcmonitoreditem) | Removes the monitored item specified by `item` from the [MonitoredItems](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#monitoreditems) of this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/). | | [RemoveMonitoredItem(IEnumerable<OpcMonitoredItem>)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#removemonitoreditem-system-collections-generic-ienumerable-of-opc-uafx-client-opcmonitoreditem) | Removes the monitored items specified by `items` from the [MonitoredItems](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#monitoreditems) of this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/). | | [RemoveMonitoredItem(params OpcMonitoredItem\[\])](#removemonitoreditem-opc-uafx-client-opcmonitoreditem-array) | Removes the monitored items specified by `items` from the [MonitoredItems](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#monitoreditems) of this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/). | #### RemoveMonitoredItem(OpcMonitoredItem) Removes the monitored item specified by `item` from the [MonitoredItems](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#monitoreditems) of this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public void RemoveMonitoredItem(OpcMonitoredItem item) ```
```vbnet Public Sub RemoveMonitoredItem(item As OpcMonitoredItem) ```
**Parameters** | Name | Type | Description | |---|---|---| | `item` | [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) | The [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) to remove. | **Exceptions** | Exception | Condition | |---|---| | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `item` is a null reference (Nothing in Visual Basic). | #### RemoveMonitoredItem(IEnumerable<OpcMonitoredItem>) Removes the monitored items specified by `items` from the [MonitoredItems](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#monitoreditems) of this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public void RemoveMonitoredItem(IEnumerable items) ```
```vbnet Public Sub RemoveMonitoredItem(items As IEnumerable(Of OpcMonitoredItem)) ```
**Parameters** | Name | Type | Description | |---|---|---| | `items` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)<[OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/)> | A sequence of [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) instances to remove. | **Exceptions** | Exception | Condition | |---|---| | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `items` is a null reference (Nothing in Visual Basic). | #### RemoveMonitoredItem(params OpcMonitoredItem\[\]) Removes the monitored items specified by `items` from the [MonitoredItems](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#monitoreditems) of this [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public void RemoveMonitoredItem(params OpcMonitoredItem[] items) ```
```vbnet Public Sub RemoveMonitoredItem(ParamArray items As OpcMonitoredItem()) ```
**Parameters** | Name | Type | Description | |---|---|---| | `items` | params [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/)[] | An array of [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/) instances to remove. | **Exceptions** | Exception | Condition | |---|---| | [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `items` is a null reference (Nothing in Visual Basic). | ### ToString override Returns a string that represents the current [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/).
```csharp public override string ToString() ```
```vbnet Public Overrides Function ToString() As String ```
**Returns** [String](https://learn.microsoft.com/dotnet/api/system.string) A string that represents the current [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) including the used [DisplayName](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#displayname), the [PublishingIsEnabled](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#publishingisenabled) and the [PublishingInterval](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionsetup/members#publishinginterval). **Overrides** [ToString()](https://learn.microsoft.com/dotnet/api/system.object.tostring)