DiscoverGlobalApplications 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
 
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Function DiscoverGlobalApplications( _
   ByVal gdsEndpointDescriptorString As String, _
   ByVal queryApplicationsFilter As Object _
) As UADiscoveryElementCollection

'Usage
 
Dim instance As _EasyUAClient
Dim gdsEndpointDescriptorString As String
Dim queryApplicationsFilter As Object
Dim value As UADiscoveryElementCollection
 
value = instance.DiscoverGlobalApplications(gdsEndpointDescriptorString, queryApplicationsFilter)

[ElementsNotNull()]
[NotNull()]
UADiscoveryElementCollection DiscoverGlobalApplications( 
   string gdsEndpointDescriptorString,
   object queryApplicationsFilter
)

[ElementsNotNull()]
[NotNull()]
UADiscoveryElementCollection^ DiscoverGlobalApplications( 
   String^ gdsEndpointDescriptorString,
   Object^ queryApplicationsFilter
)

Parameters

gdsEndpointDescriptorString
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

_EasyUAClient Interface
_EasyUAClient Members

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