OPCDA.NET Reference Manual
Read Method
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OpcDaNetUA.Net4 Assembly > OPCDA.NET.Controls Namespace > DAGroup Class : Read Method

itemDefs
Array of item identifiers. ItemDefinitionSets defined in the Visual Studio Designer can be used as the as the argument.
tag
This object is passed to the competion handler and allows the user to pass any information that may be needed in the completion handler. Nothing (null) can be specified if the application does not require to pass any information.
onCompleted
Competion notification handler. void xxx(BGException ex, DAItemValue[] rslt, object tag){}

Glossary Item Box

Available in the OPCDA.NET Professional Edition only.
Read a set of items by executing an asynchronous read call in the background thread of the BGGroup class. The call returns immediately after the request is queued. The success of the call is reported in the completion event handler arguments. Complete failure is indicated in the exception argument. Error reading certain items are reported in the Error field of the rslt object.

Syntax

Visual Basic (Declaration) 
Public Sub Read( _
   ByVal itemDefs() As DAItemValue, _
   ByVal tag As Object, _
   ByVal onCompleted As DAReadComplete _
)

Parameters

itemDefs
Array of item identifiers. ItemDefinitionSets defined in the Visual Studio Designer can be used as the as the argument.
tag
This object is passed to the competion handler and allows the user to pass any information that may be needed in the completion handler. Nothing (null) can be specified if the application does not require to pass any information.
onCompleted
Competion notification handler. void xxx(BGException ex, DAItemValue[] rslt, object tag){}

Requirements

Target Platforms: Windows 7/8/10, Windows Server 2003/2008/2012/2016, .NET 4.x

See Also

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