'Declaration
 
<ExtensionAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function ReadFunction(Of TValue)( _
   ByVal dataVariable As UADataVariable, _
   ByVal readFunction As Func(Of UAAttributeData(Of TValue)), _
   ByVal ParamArray arrayDimensions() As Integer _
) As UADataVariable

'Usage
 
Dim dataVariable As UADataVariable
Dim readFunction As Func(Of UAAttributeData(Of TValue))
Dim arrayDimensions() As Integer
Dim value As UADataVariable
 
value = UADataVariableExtension.ReadFunction(Of TValue)(dataVariable, readFunction, arrayDimensions)

[Extension()]
[NotNull()]
public static UADataVariable ReadFunction<TValue>( 
   UADataVariable dataVariable,
   Func<UAAttributeData<TValue>> readFunction,
   params int[] arrayDimensions
)

[Extension()]
[NotNull()]
public:
static UADataVariable^ ReadFunctiongeneric<typename TValue>
( 
   UADataVariable^ dataVariable,
   Func<UAAttributeData<TValue^>^>^ readFunction,
   ... array<int>^ arrayDimensions
) 

Parameters

dataVariable

The data variable that will be modified and returned.

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

readFunction

The read function, i.e. the function that performs the read operation and returns the attribute data that will be returned to the caller of the OPC UA Read.

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

arrayDimensions

The size of each dimension of the array value.

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

Type Parameters

TValue

The type of the value of the data variable.

Return Value

This method overload infers the OPC data type of the data variable from the TValue type.

The array dimensions are specified as a list of integers, one for each dimension. Each element represents a dimension of the array, and the value of the element represents the maximum size of the array in that dimension. If the maximum size of certain dimension is unknown, the value of corresponding element is 0.

The specified array dimensions will be stored in the ArrayDimensions property, and exposed to OPC UA clients via the OpcLabs.EasyOpc.UA.UAAttributeId.ArrayDimensions attribute. In addition, OPC Wizard will enforce the maximum array bounds automatically (where the specified array dimension is not 0).

When you use the method overload without the array dimensions (arrayDimensions parameter), the method determines the array dimensions automatically from the TValue type parameter, and if the type is an array, the individual dimension elements are set to 0, meaning that the size of the array is not limited in any dimension. If you want to limit the size of the array in certain dimensions, you need to use this method overload (with arrayDimensions parameter), and specify the array dimensions explicitly.

In languages that support parameter arrays (methods with variable number of arguments), such as C# or VB.NET, the arrayDimensions parameter can be specified as one or more arguments of type System.Int32, without having to construct the array of dimensions explicitly.

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