QuickOPC User's Guide and Reference
TestSubscription Method



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.PubSub.Extensions Namespace > IEasyUASubscriberExtension2 Class : TestSubscription Method
The subscriber object that will perform the operation.
Arguments needed to subscribe to a dataset.
A period during which a dataset should be received.
Tests whether an OPC UA PubSub subscription can be successfully established. Synchronous.
Syntax
'Declaration
 
<ExtensionAttribute()>
<CanBeNullAttribute()>
Public Shared Function TestSubscription( _
   ByVal subscriber As IEasyUASubscriber, _
   ByVal subscribeDataSetArguments As UASubscribeDataSetArguments, _
   ByVal millisecondsTimeout As Integer _
) As UADataSetData
'Usage
 
Dim subscriber As IEasyUASubscriber
Dim subscribeDataSetArguments As UASubscribeDataSetArguments
Dim millisecondsTimeout As Integer
Dim value As UADataSetData
 
value = IEasyUASubscriberExtension2.TestSubscription(subscriber, subscribeDataSetArguments, millisecondsTimeout)

Parameters

subscriber
The subscriber object that will perform the operation.
subscribeDataSetArguments
Arguments needed to subscribe to a dataset.
millisecondsTimeout
A period during which a dataset should be received.

Return Value

The method returns a non-null OpcLabs.EasyOpc.UA.PubSub.UADataSetData when the test passes and a dataset has been received, or a null reference if there is no error, but no dataset has been received during the millisecondsTimeout period. The method throws a OpcLabs.EasyOpc.UA.OperationModel.UAException when there is an error establishing the subscription.
Exceptions
ExceptionDescription

A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

The value of an argument is outside the allowable range of values as defined by the invoked method.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

The task has been cancelled.

The OPC UA operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause.

This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

Remarks

This is a synchronous method. For an asynchronous alternative, see TestSubscriptionAsync.

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also