WriteItemValue(IEasyDAClient,ServerDescriptor,DAItemDescriptor,Object) Method

Writes a value into a named item in an OPC server. Only the item value is written (quality and timestamp are not written). Writes a value into a named item using descriptor objects for the OPC server and OPC-DA item.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Sub WriteItemValue( _
   ByVal client As IEasyDAClient, _
   ByVal serverDescriptor As ServerDescriptor, _
   ByVal itemDescriptor As DAItemDescriptor, _
   ByVal value As Object _
)

'Usage
 
Dim client As IEasyDAClient
Dim serverDescriptor As ServerDescriptor
Dim itemDescriptor As DAItemDescriptor
Dim value As Object
 
IEasyDAClientExtension.WriteItemValue(client, serverDescriptor, itemDescriptor, value)

[Extension()]
public static void WriteItemValue( 
   IEasyDAClient client,
   ServerDescriptor serverDescriptor,
   DAItemDescriptor itemDescriptor,
   object value
)

[Extension()]
public:
static void WriteItemValue( 
   IEasyDAClient^ client,
   ServerDescriptor^ serverDescriptor,
   DAItemDescriptor^ itemDescriptor,
   Object^ value
)

Parameters

client: The client object that will perform the operation.
serverDescriptor: The OPC server involved in the operation.
itemDescriptor: The OPC item involved in the operation.
value: The value to be written.

Exceptions

Exception Description

Exception	Description
System.ArgumentNullException	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.
OpcLabs.EasyOpc.OperationModel.OpcException	The OPC "Classic" (or OPC XML-DA) operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause. This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

System.ArgumentNullException

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.

OpcLabs.EasyOpc.OperationModel.OpcException

The OPC "Classic" (or OPC XML-DA) operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause.

This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

Remarks

The server can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

Requirements

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

Reference

IEasyDAClientExtension Class
IEasyDAClientExtension Members
Overload List

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