Connectivity Software User's Guide and Reference
ReadWrite(SparkplugMetric,Type,SparkplugData) Method



OpcLabs.EasySparkplug Assembly > OpcLabs.EasySparkplug Namespace > SparkplugMetricExtension Class > ReadWrite Method : ReadWrite(SparkplugMetric,Type,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 initial Sparkplug data of the metric.

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

Makes the metric into a read-write register, specifying value type and initial Sparkplug data (value, timestamp).
Syntax
'Declaration
 
<ExtensionAttribute()>
<JetBrains.Annotations.NotNullAttribute()>
Public Overloads Shared Function ReadWrite( _
   ByVal metric As SparkplugMetric, _
   ByVal valueType As Type, _
   ByVal data As SparkplugData _
) As SparkplugMetric
'Usage
 
Dim metric As SparkplugMetric
Dim valueType As Type
Dim data As SparkplugData
Dim value As SparkplugMetric
 
value = SparkplugMetricExtension.ReadWrite(metric, valueType, data)
[Extension()]
[JetBrains.Annotations.NotNull()]
public static SparkplugMetric ReadWrite( 
   SparkplugMetric metric,
   Type valueType,
   SparkplugData data
)
[Extension()]
[JetBrains.Annotations.NotNull()]
public:
static SparkplugMetric^ ReadWrite( 
   SparkplugMetric^ metric,
   Type^ valueType,
   SparkplugData^ data
) 

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).

data
The initial Sparkplug data of the metric.

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 method makes the metric both readable and writable. The data written to the metric will become the data subsequently read from the metric.

This method also makes the timestamp of the metric writable, i.e. Sparkplug host applications will be able to modify its value. If you need a different behavior, call the Writable(SparkplugMetric,Boolean) method subsequently, with the desired parameter, or modify the WritableTimestamp accordingly (set it to false).

In order to make a read-write register of certain type, but without having to specify initial data, consider simply using one of the ValueType(SparkplugMetric,Type) overloads.

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