QuerySourceConditions Method (IEasyAEClient)

Finds out event conditions associated with the specified source name. Uses server descriptor for specifying the OPC server.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Function QuerySourceConditions( _
   ByVal serverDescriptor As ServerDescriptor, _
   ByVal sourceNodeDescriptor As AENodeDescriptor _
) As AEConditionElementCollection

'Usage
 
Dim instance As IEasyAEClient
Dim serverDescriptor As ServerDescriptor
Dim sourceNodeDescriptor As AENodeDescriptor
Dim value As AEConditionElementCollection
 
value = instance.QuerySourceConditions(serverDescriptor, sourceNodeDescriptor)

[ElementsNotNull()]
[NotNull()]
AEConditionElementCollection QuerySourceConditions( 
   ServerDescriptor serverDescriptor,
   AENodeDescriptor sourceNodeDescriptor
)

[ElementsNotNull()]
[NotNull()]
AEConditionElementCollection^ QuerySourceConditions( 
   ServerDescriptor^ serverDescriptor,
   AENodeDescriptor^ sourceNodeDescriptor
)

Parameters

serverDescriptor: The OPC server involved in the operation.
sourceNodeDescriptor: A source node descriptor, usually expressed as qualified source name. Only the conditions associated with this source are returned.

Return Value

A collection of condition elements, one element for each condition of the given source.

Exceptions

Exception	Description
OpcLabs.EasyOpc.OperationModel.OpcException	The OPC "Classic" (or OPC XML-DA) operation has failed.
System.ArgumentNullException	A `null` reference (`Nothing` in Visual Basic) is passed to a method that does not accept it as a valid argument.

Example

CSharp
VB.NET

// This example shows how to enumerate all event conditions associated with the specified event source.

using System;
using System.Diagnostics;
using OpcLabs.EasyOpc.AlarmsAndEvents;
using OpcLabs.EasyOpc.AlarmsAndEvents.AddressSpace;
using OpcLabs.EasyOpc.OperationModel;

namespace DocExamples.AlarmsAndEvents._EasyAEClient
{
    class QuerySourceConditions 
    { 
        public static void Main1()
        {
            // Instantiate the client object.
            var client = new EasyAEClient();

            AEConditionElementCollection conditionElements;
            try
            {
                conditionElements = client.QuerySourceConditions("", "OPCLabs.KitEventServer.2", 
                    "Simulation.ConditionState1");
            }
            catch (OpcException opcException)
            {
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
                return;
            }

            foreach (AEConditionElement conditionElement in conditionElements)
            {
                Debug.Assert(conditionElement != null);
                Console.WriteLine("ConditionElements[\"{0}\"]: {1} subcondition(s)", 
                    conditionElement.Name, conditionElement.SubconditionNames.Length);
            }
        }
    } 
}

' This example shows how to enumerate all event conditions associated with the specified event source.

Imports OpcLabs.EasyOpc.AlarmsAndEvents
Imports OpcLabs.EasyOpc.AlarmsAndEvents.AddressSpace
Imports OpcLabs.EasyOpc.OperationModel

Namespace DocExamples.AlarmsAndEvents._EasyAEClient

    Friend Class QuerySourceConditions
        Public Shared Sub Main1()
            Dim client = New EasyAEClient()

            Dim conditionElements As AEConditionElementCollection
            Try
                conditionElements = client.QuerySourceConditions( _
                    "", "OPCLabs.KitEventServer.2", "Simulation.ConditionState1")
            Catch opcException As OpcException
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
                Exit Sub
            End Try

            For Each conditionElement As AEConditionElement In conditionElements
                Debug.Assert(conditionElement IsNot Nothing)
                Console.WriteLine("ConditionElements[""{0}""]: {1} subcondition(s)", _
                                  conditionElement.Name, conditionElement.SubconditionNames.Length)
            Next conditionElement
        End Sub
    End Class

End Namespace

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

IEasyAEClient Interface
IEasyAEClient Members