QuickOPC User's Guide and Reference
GetConditionState(IEasyAEClient,ServerDescriptor,AENodeDescriptor,String) Method
Example 



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OpcLabs.EasyOpcClassicCore Assembly > OpcLabs.EasyOpc.AlarmsAndEvents Namespace > IEasyAEClientExtension Class > GetConditionState Method : GetConditionState(IEasyAEClient,ServerDescriptor,AENodeDescriptor,String) Method
The client object that will perform the operation.
The OPC server involved in the operation.
Contains fully qualified source name, as returned by browsing. The state of the condition instance associated with this source is returned.
A condition name, as returned by querying. The state of this condition is returned.
Returns the current state information for the condition instance corresponding to the source and condition name. Returns the current state information for the condition instance corresponding to the source and condition name, passing in a server descriptor. No event attributes are returned.
Syntax
'Declaration
 
<ExtensionAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function GetConditionState( _
   ByVal client As IEasyAEClient, _
   ByVal serverDescriptor As ServerDescriptor, _
   ByVal sourceDescriptor As AENodeDescriptor, _
   ByVal conditionName As String _
) As AEConditionState
 
'Usage
 
Dim client As IEasyAEClient
Dim serverDescriptor As ServerDescriptor
Dim sourceDescriptor As AENodeDescriptor
Dim conditionName As String
Dim value As AEConditionState
 
value = IEasyAEClientExtension.GetConditionState(client, serverDescriptor, sourceDescriptor, conditionName)

Parameters

client
The client object that will perform the operation.
serverDescriptor
The OPC server involved in the operation.
sourceDescriptor
Contains fully qualified source name, as returned by browsing. The state of the condition instance associated with this source is returned.
conditionName
A condition name, as returned by querying. The state of this condition is returned.

Return Value

If successful, the function returns a AEConditionState object. The object contains information about the state of the condition.
Exceptions
ExceptionDescription

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 OPC "Classic" (or OPC XML-DA) operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause.

This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

Remarks

The server can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

Some servers may not maintain sufficient condition state information to fully implement this method.

Example

.NET

.NET

// This example shows how to obtain current state information for the condition instance corresponding to a Source and 
// certain ConditionName.

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

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

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

            Console.WriteLine("ConditionState:");
            Console.WriteLine("    .ActiveSubcondition: {0}", conditionState.ActiveSubcondition);
            Console.WriteLine("    .Enabled: {0}", conditionState.Enabled);
            Console.WriteLine("    .Active: {0}", conditionState.Active);
            Console.WriteLine("    .Acknowledged: {0}", conditionState.Acknowledged);
            Console.WriteLine("    .Quality: {0}", conditionState.Quality);
            // Remark: IAEConditionState has many more properties
        }
    } 
}
// This example shows how to obtain current state information for the condition instance corresponding to a Source and 
// certain ConditionName.

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

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

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

            Console.WriteLine("ConditionState:");
            Console.WriteLine("    .ActiveSubcondition: {0}", conditionState.ActiveSubcondition);
            Console.WriteLine("    .Enabled: {0}", conditionState.Enabled);
            Console.WriteLine("    .Active: {0}", conditionState.Active);
            Console.WriteLine("    .Acknowledged: {0}", conditionState.Acknowledged);
            Console.WriteLine("    .Quality: {0}", conditionState.Quality);
            // Remark: IAEConditionState has many more properties
        }
    } 
}
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