OPC Studio User's Guide and Reference
HasCapability Method



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.Discovery.Extensions Namespace > UAApplicationElementExtension Class : HasCapability Method
The application element to be examined.

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

The capability identifier.

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

Determines whether the application supports the specified capability.
Syntax
'Declaration
 
<ExtensionAttribute()>
Public Shared Function HasCapability( _
   ByVal applicationElement As UAApplicationElement, _
   ByVal capabilityIdentifier As String _
) As Nullable(Of Boolean)
'Usage
 
Dim applicationElement As UAApplicationElement
Dim capabilityIdentifier As String
Dim value As Nullable(Of Boolean)
 
value = UAApplicationElementExtension.HasCapability(applicationElement, capabilityIdentifier)

Parameters

applicationElement
The application element to be examined.

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

capabilityIdentifier
The capability identifier.

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

Return Value

Returns true when the application described by the applicationElement supports the capability given by capabilityIdentifier. Returns false when the application described by the applicationElement does not support the capability given by capabilityIdentifier. Returns null when the capability information for the server is not available.
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

The server capability identifiers are described in Annex D of OPC UA Part 12. For normative list, see http://www.opcfoundation.org/UA/schemas/1.04/ServerCapabilities.csv .

This is an extension method (info: C#, VB.NET). In languages that have support for extensions methods (such as C# and VB.NET), you can use the extension method as if it were a regular method on the object that is its first parameter. In other languages (such as with Python.NET), you will call the extension as a static method, and pass it the object on which it acts as its first parameter.

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