'Declaration
 
<ExtensionAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function Constant( _
   ByVal dataVariable As UADataVariable, _
   ByVal dataTypeId As UANodeId, _
   ByVal attributeData As UAAttributeData _
) As UADataVariable

'Usage
 
Dim dataVariable As UADataVariable
Dim dataTypeId As UANodeId
Dim attributeData As UAAttributeData
Dim value As UADataVariable
 
value = UADataVariableExtension.Constant(dataVariable, dataTypeId, attributeData)

[Extension()]
[NotNull()]
public static UADataVariable Constant( 
   UADataVariable dataVariable,
   UANodeId dataTypeId,
   UAAttributeData attributeData
)

[Extension()]
[NotNull()]
public:
static UADataVariable^ Constant( 
   UADataVariable^ dataVariable,
   UANodeId^ dataTypeId,
   UAAttributeData^ attributeData
) 

Parameters

dataVariable

The data variable that will be modified and returned.

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

dataTypeId

Specifies the OPC UA data type of the variable value. For standard data types, see OpcLabs.EasyOpc.UA.AddressSpace.Standard.UADataTypeIds.

Because the OpcLabs.EasyOpc.UA.AddressSpace.UANodeId has an implicit conversion from System.String, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a string (representing the expanded text of the nodeId) in place of this parameter, and the corresponding OPC UA node Id will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the OpcLabs.EasyOpc.UA.AddressSpace.UANodeId.UANodeId Constructor(String) constructor instead.

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

attributeData

The constant attribute data that will be provided by the data variable.

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

Return Value

The data variable is made read-only, and its minimum sampling interval is set to System.Threading.Timeout.Infinite, effectively disabling the sampling.

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.

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