WaitForMultipleItems(IEasyDAClient,IReadOnlyList<ValueTuple<DAItemGroupArguments,Func<DAVtqResult,Boolean>>>) Method

Subscribes to the specified OPC-DA items, and monitors their data until the predicates specified for each item become true, or the alloted time elapses.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function WaitForMultipleItems( _
   ByVal client As IEasyDAClient, _
   ByVal argumentsAndExitPredicateList As IReadOnlyList(Of ValueTuple(Of DAItemGroupArguments,Func(Of DAVtqResult,Boolean))) _
) As DAVtqResult()

'Usage
 
Dim client As IEasyDAClient
Dim argumentsAndExitPredicateList As IReadOnlyList(Of ValueTuple(Of DAItemGroupArguments,Func(Of DAVtqResult,Boolean)))
Dim value() As DAVtqResult
 
value = IEasyDAClientExtension2.WaitForMultipleItems(client, argumentsAndExitPredicateList)

[Extension()]
[ElementsNotNull()]
[NotNull()]
public static DAVtqResult[] WaitForMultipleItems( 
   IEasyDAClient client,
   IReadOnlyList<ValueTuple<DAItemGroupArguments,Func<DAVtqResult,bool>>> argumentsAndExitPredicateList
)

[Extension()]
[ElementsNotNull()]
[NotNull()]
public:
static array<DAVtqResult^>^ WaitForMultipleItems( 
   IEasyDAClient^ client,
   IReadOnlyList<ValueTuple<DAItemGroupArguments^,Func<DAVtqResult^,bool>^>>^ argumentsAndExitPredicateList
)

Parameters

client: The client object that will perform the operation.
argumentsAndExitPredicateList: List of tuples, where each tuple consists of OPC-DA item group arguments, and a predicate on OpcLabs.EasyOpc.DataAccess.OperationModel.DAVtqResult determining when the wait is complete.

Return Value

The function returns an array of OpcLabs.EasyOpc.DataAccess.OperationModel.DAVtqResult objects. The indices of elements in the output array are the same as those in the input list, .

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.

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.

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

IEasyDAClientExtension2 Class
IEasyDAClientExtension2 Members
Overload List

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