Connectivity Software User's Guide and Reference
ReadFunction(SparkplugMetric,Type,Func<SparkplugData>) Method



OpcLabs.EasySparkplug Assembly > OpcLabs.EasySparkplug Namespace > SparkplugMetricExtension Class > ReadFunction Method : ReadFunction(SparkplugMetric,Type,Func<SparkplugData>) Method
The Sparkplug metric that will perform the operation.

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

The type of the Sparkplug metric, expressed as .NET System.Type.

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

The read function, i.e. the function that performs the read operation and returns the Sparkplug data that will be published.

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

Specifies value type, and read function returning Sparkplug data, for the pull data provision model.
Syntax
'Declaration
 
<ExtensionAttribute()>
<JetBrains.Annotations.NotNullAttribute()>
Public Overloads Shared Function ReadFunction( _
   ByVal metric As SparkplugMetric, _
   ByVal valueType As Type, _
   ByVal readFunction As Func(Of SparkplugData) _
) As SparkplugMetric
'Usage
 
Dim metric As SparkplugMetric
Dim valueType As Type
Dim readFunction As Func(Of SparkplugData)
Dim value As SparkplugMetric
 
value = SparkplugMetricExtension.ReadFunction(metric, valueType, readFunction)
[Extension()]
[JetBrains.Annotations.NotNull()]
public static SparkplugMetric ReadFunction( 
   SparkplugMetric metric,
   Type valueType,
   Func<SparkplugData> readFunction
)
[Extension()]
[JetBrains.Annotations.NotNull()]
public:
static SparkplugMetric^ ReadFunction( 
   SparkplugMetric^ metric,
   Type^ valueType,
   Func<SparkplugData^>^ readFunction
) 

Parameters

metric
The Sparkplug metric that will perform the operation.

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

valueType
The type of the Sparkplug metric, expressed as .NET System.Type.

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 Sparkplug data that will be published.

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

Return Value

Returns the metric, internally modified as defined by the method.

This method never returns 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.

Remarks

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.

 

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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