OPC Studio User's Guide and Reference
Subscribe(Boolean,IEnumerable<UAMapping>) Method



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.LiveMapping Namespace > UAClientMapper Class > Subscribe Method : Subscribe(Boolean,IEnumerable<UAMapping>) Method
true to subscribe; false to unsubscribe.
The mappings to be operated upon.

The value of this parameter cannot be null (Nothing in Visual Basic).

Executes the "Subscribe" operation on given mappings.
Syntax
'Declaration
 
Public Overloads Sub Subscribe( _
   ByVal active As Boolean, _
   ByVal mappings As IEnumerable(Of UAMapping) _
) 
'Usage
 
Dim instance As UAClientMapper
Dim active As Boolean
Dim mappings As IEnumerable(Of UAMapping)
 
instance.Subscribe(active, mappings)
public void Subscribe( 
   bool active,
   IEnumerable<UAMapping> mappings
)
public:
void Subscribe( 
   bool active,
   IEnumerable<UAMapping^>^ mappings
) 

Parameters

active
true to subscribe; false to unsubscribe.
mappings
The mappings to be operated upon.

The value of this parameter cannot be null (Nothing in Visual Basic).

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 component is not licensed for the operation requested.
Remarks
The "Subscribe" operation subscribes to or unsubscribes from changes of an OPC node. Only mappings of type UAClientDataMapping that include UADataMappingOperations.Subscribe in their UAClientDataMapping.Operations are affected; other mappings are ignored.
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