OPC Studio User's Guide and Reference
EasyUAMonitoredItemArguments Constructor(EasyUADataChangeNotificationEventHandler,Object,UAEndpointDescriptor,UANodeDescriptor)



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.OperationModel Namespace > EasyUAMonitoredItemArguments Class > EasyUAMonitoredItemArguments Constructor : EasyUAMonitoredItemArguments Constructor(EasyUADataChangeNotificationEventHandler,Object,UAEndpointDescriptor,UANodeDescriptor)
A callback method to be invoked for each significant monitored item change.
User-defined state object.
Endpoint descriptor. Identifies the OPC-UA server.
Node descriptor. Identifies the node in OPC server's address space.
Initializes a new instance of the class.
Syntax
'Declaration
 
Public Function New( _
   ByVal dataChangeCallback As EasyUADataChangeNotificationEventHandler, _
   ByVal state As Object, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal nodeDescriptor As UANodeDescriptor _
)
'Usage
 
Dim dataChangeCallback As EasyUADataChangeNotificationEventHandler
Dim state As Object
Dim endpointDescriptor As UAEndpointDescriptor
Dim nodeDescriptor As UANodeDescriptor
 
Dim instance As New EasyUAMonitoredItemArguments(dataChangeCallback, state, endpointDescriptor, nodeDescriptor)

Parameters

dataChangeCallback
A callback method to be invoked for each significant monitored item change.
state
User-defined state object.
endpointDescriptor
Endpoint descriptor. Identifies the OPC-UA server.
nodeDescriptor
Node descriptor. Identifies the node in OPC server's address space.
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.

Remarks

If dataChangeCallback is a null reference, only the OpcLabs.EasyOpc.UA.EasyUAClientCore.DataChangeNotification event is generated, and no callback method is invoked.

You can obtain nodeDescriptor e.g. by calling one of the browsing methods on OpcLabs.EasyOpc.UA.EasyUAClientCore object.

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