ReadItemValueChar(IEasyDAClient,ServerDescriptor,DANodeDescriptor) Method

Reads a value of named OPC item, and converts it to System.Char. The value is requested from the OPC server using a corresponding data type.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Function ReadItemValueChar( _
   ByVal client As IEasyDAClient, _
   ByVal serverDescriptor As ServerDescriptor, _
   ByVal nodeDescriptor As DANodeDescriptor _
) As Char

'Usage
 
Dim client As IEasyDAClient
Dim serverDescriptor As ServerDescriptor
Dim nodeDescriptor As DANodeDescriptor
Dim value As Char
 
value = IEasyDAClientExtension2.ReadItemValueChar(client, serverDescriptor, nodeDescriptor)

[Extension()]
public static char ReadItemValueChar( 
   IEasyDAClient client,
   ServerDescriptor serverDescriptor,
   DANodeDescriptor nodeDescriptor
)

[Extension()]
public:
static char ReadItemValueChar( 
   IEasyDAClient^ client,
   ServerDescriptor^ serverDescriptor,
   DANodeDescriptor^ nodeDescriptor
)

Parameters

client: The client object that will perform the operation.
serverDescriptor: The OPC server involved in the operation.
nodeDescriptor: The descriptor of the OPC node involved in the operation.

Return Value

Returns a value of the OPC item, converted to a type indicated by the method name.

Exceptions

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.
OpcLabs.EasyOpc.OperationModel.OpcException	The OPC "Classic" (or OPC XML-DA) operation has failed.

Remarks

Using implicit conversions, you can pass an item ID in place of node descriptor.

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2012, Windows Server 2016; .NET Core, .NET 5, .NET 6: Linux, macOS, Microsoft Windows

Reference

IEasyDAClientExtension2 Class
IEasyDAClientExtension2 Members
Overload List