QuickOPC User's Guide and Reference
ReadTarget(DAClientMapper,Object,String,Boolean) Method



OpcLabs.EasyOpcClassic Assembly > OpcLabs.EasyOpc.DataAccess.LiveMapping.Extensions Namespace > DAClientMapperExtension Class > ReadTarget Method : ReadTarget(DAClientMapper,Object,String,Boolean) Method
The client mapper object that will perform the operation.
The object being targeted.
The operation will be performed only on mappings tagged with this mapping tag.
true to operate on sub-targets (mapped members of the target) recursively; false otherwise.
Executes the "Read" operation on members of given target object.
Syntax
'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Sub ReadTarget( _
   ByVal clientMapper As DAClientMapper, _
   ByVal targetObject As Object, _
   ByVal mappingTag As String, _
   ByVal recurse As Boolean _
) 
'Usage
 
Dim clientMapper As DAClientMapper
Dim targetObject As Object
Dim mappingTag As String
Dim recurse As Boolean
 
DAClientMapperExtension.ReadTarget(clientMapper, targetObject, mappingTag, recurse)

Parameters

clientMapper
The client mapper object that will perform the operation.
targetObject
The object being targeted.
mappingTag
The operation will be performed only on mappings tagged with this mapping tag.
recurse
true to operate on sub-targets (mapped members of the target) recursively; false otherwise.
Exceptions
ExceptionDescription

One of the arguments provided to a method is not valid.

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.

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.

The component is not licensed for the operation requested.
Remarks
The "Read" operation reads a value of an OPC item and stores it into the mapping source. Only mappings of type OpcLabs.EasyOpc.DataAccess.LiveMapping.DAItemMapping that include OpcLabs.EasyOpc.DataAccess.LiveMapping.DAItemMappingOperations.Read in their OpcLabs.EasyOpc.DataAccess.LiveMapping.DAClientItemMapping.Operations are affected; other mappings are ignored.
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