DiscoverGlobalApplications(IEasyUAClient,UAEndpointDescriptor,UAQueryApplicationsFilter) Method

Globally discovers OPC-UA applications that meet the specified filters and returns information about them, using the specified GDS endpoint.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function DiscoverGlobalApplications( _
   ByVal client As IEasyUAClient, _
   ByVal gdsEndpointDescriptor As UAEndpointDescriptor, _
   ByVal queryApplicationsFilter As UAQueryApplicationsFilter _
) As UADiscoveryElementCollection

'Usage
 
Dim client As IEasyUAClient
Dim gdsEndpointDescriptor As UAEndpointDescriptor
Dim queryApplicationsFilter As UAQueryApplicationsFilter
Dim value As UADiscoveryElementCollection
 
value = IEasyUAClientExtension.DiscoverGlobalApplications(client, gdsEndpointDescriptor, queryApplicationsFilter)

[Extension()]
[ElementsNotNull()]
[NotNull()]
public static UADiscoveryElementCollection DiscoverGlobalApplications( 
   IEasyUAClient client,
   UAEndpointDescriptor gdsEndpointDescriptor,
   UAQueryApplicationsFilter queryApplicationsFilter
)

[Extension()]
[ElementsNotNull()]
[NotNull()]
public:
static UADiscoveryElementCollection^ DiscoverGlobalApplications( 
   IEasyUAClient^ client,
   UAEndpointDescriptor^ gdsEndpointDescriptor,
   UAQueryApplicationsFilter^ queryApplicationsFilter
)

Parameters

client: The client object that will perform the operation.
gdsEndpointDescriptor: The endpoint descriptor of the Global Discover Server (GDS) that will be used for performing the discovery.
queryApplicationsFilter: A filter used to find servers that meet the specified criteria.

Return Value

Returns a collection of application elements (servers, OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElement).

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.
OpcLabs.EasyOpc.UA.OperationModel.UAException	The OPC UA 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.

OpcLabs.EasyOpc.UA.OperationModel.UAException

The OPC UA 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

This method uses the so-called OPC UA Global Discovery Server (GDS).

See also in Knowledge Base: Technical note-OPC UA Discovery in QuickOPC.

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

IEasyUAClientExtension Class
IEasyUAClientExtension Members
Overload List

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