GetConditionState Method (IEasyAEClient)

Returns the current state information for the condition instance corresponding to the source and condition name, passing in a server descriptor. Also allows to retrieve specified event attributes.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<NotNullAttribute()>
Function GetConditionState( _
   ByVal serverDescriptor As ServerDescriptor, _
   ByVal sourceDescriptor As AENodeDescriptor, _
   ByVal conditionName As String, _
   ByVal attributes() As Long _
) As AEConditionState

'Usage
 
Dim instance As IEasyAEClient
Dim serverDescriptor As ServerDescriptor
Dim sourceDescriptor As AENodeDescriptor
Dim conditionName As String
Dim attributes() As Long
Dim value As AEConditionState
 
value = instance.GetConditionState(serverDescriptor, sourceDescriptor, conditionName, attributes)

[NotNull()]
AEConditionState GetConditionState( 
   ServerDescriptor serverDescriptor,
   AENodeDescriptor sourceDescriptor,
   string conditionName,
   long[] attributes
)

[NotNull()]
AEConditionState^ GetConditionState( 
   ServerDescriptor^ serverDescriptor,
   AENodeDescriptor^ sourceDescriptor,
   String^ conditionName,
   array<int64>^ attributes
)

Parameters

serverDescriptor

The OPC server involved in the operation.

Because the OpcLabs.EasyOpc.ServerDescriptor has an implicit conversion from System.Guid, System.String and OpcLabs.EasyOpc.ServerElement, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a GUID (representing the CLSID of the server), a string (representing the so-called OPC server descriptor string, such as a ProgID or the URL of the server), or a OpcLabs.EasyOpc.ServerElement object (result from OPC browsing), in place of this parameter, and the corresponding OPC server descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the FromGuid, FromString or FromServerElement static method instead.

The value of this parameter cannot be null (Nothing in Visual Basic).

sourceDescriptor

Contains fully qualified source name, as returned by browsing. The state of the condition instance associated with this source is returned.

Because the AENodeDescriptor has an implicit conversion from System.String and OpcLabs.EasyOpc.AlarmsAndEvents.AddressSpace.AENodeElement, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a string (representing the qualified name of the node), or a OpcLabs.EasyOpc.AlarmsAndEvents.AddressSpace.AENodeElement object (result from OPC browsing), in place of this parameter, and the corresponding OPC A&E node descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the AENodeDescriptor.FromString or AENodeDescriptor.FromAENodeElement static method instead.

The value of this parameter cannot be null (Nothing in Visual Basic).

conditionName

A condition name, as returned by querying. The state of this condition is returned.

The value of this parameter cannot be null (Nothing in Visual Basic).

attributes

Specifies the event attributes to be returned.

The value of this parameter cannot be null (Nothing in Visual Basic).

Return Value

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

This method never returns null (Nothing in Visual Basic).

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.ArgumentOutOfRangeException	The value of an argument is outside the allowable range of values as defined by the invoked method. 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.
OpcLabs.EasyOpc.OperationModel.OpcException	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.

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.ArgumentOutOfRangeException

The value of an argument is outside the allowable range of values as defined by the invoked method.

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.

OpcLabs.EasyOpc.OperationModel.OpcException

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

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

The server(s) can be local or can be remotely accessed via DCOM.

Example

CSharp
VB.NET
Python

// This example shows how to obtain current state information for the condition instance corresponding to a Source and 
// certain ConditionName.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

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.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET .
' Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
' a commercial license in order to use Online Forums, and we reply to every post.

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

Namespace AlarmsAndEvents._EasyAEClient

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

            Dim conditionState As AEConditionState
            Try
                conditionState = client.GetConditionState("", "OPCLabs.KitEventServer.2", "Simulation.ConditionState1", "Simulated")
            Catch opcException As OpcException
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
                Exit Sub
            End Try

            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
        End Sub
    End Class

End Namespace

# This example shows how to obtain current state information for the condition instance corresponding to a Source and 
# certain ConditionName.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python .
# Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
# a commercial license in order to use Online Forums, and we reply to every post.
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from OpcLabs.EasyOpc import *
from OpcLabs.EasyOpc.AlarmsAndEvents import *
from OpcLabs.EasyOpc.OperationModel import *


# Instantiate the client object
client = EasyAEClient()

print('Getting condition state...')
try:
    conditionState = IEasyAEClientExtension.GetConditionState(client,
        '', 'OPCLabs.KitEventServer.2', 'Simulation.ConditionState1', 'Simulated')
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message)
    exit()

print('ConditionState:')
print('    .ActiveSubcondition: ', conditionState.ActiveSubcondition)
print('    .Enabled: ', conditionState.Enabled)
print('    .Active: ', conditionState.Active)
print('    .Acknowledged: ', conditionState.Acknowledged)
print('    .Quality: ', conditionState.Quality)
# Note that IAEConditionState has many more properties

print()
print('Finished.')

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

IEasyAEClient Interface
IEasyAEClient Members

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