QuickOPC User's Guide and Reference
FindLocalApplications(IEasyUAClient,IEnumerable<String>,UAApplicationTypes,Boolean) Method



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA Namespace > IEasyUAClientExtension Class > FindLocalApplications Method : FindLocalApplications(IEasyUAClient,IEnumerable<String>,UAApplicationTypes,Boolean) Method
The client object that will perform the operation.
Discovery URI strings.
Application types to be discovered.
Determines whether one element will be returned for each discovery URI.
Discovers available OPC-UA applications and returns information about them, using the specified discovery URI strings and filtering by specified application types.
Syntax
'Declaration
 
<ExtensionAttribute()>
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function FindLocalApplications( _
   ByVal client As IEasyUAClient, _
   ByVal discoveryUriStrings As IEnumerable(Of String), _
   ByVal applicationTypes As UAApplicationTypes, _
   ByVal flat As Boolean _
) As UADiscoveryElementCollection
'Usage
 
Dim client As IEasyUAClient
Dim discoveryUriStrings As IEnumerable(Of String)
Dim applicationTypes As UAApplicationTypes
Dim flat As Boolean
Dim value As UADiscoveryElementCollection
 
value = IEasyUAClientExtension.FindLocalApplications(client, discoveryUriStrings, applicationTypes, flat)

Parameters

client
The client object that will perform the operation.
discoveryUriStrings
Discovery URI strings.
applicationTypes
Application types to be discovered.
flat
Determines whether one element will be returned for each discovery URI.

Return Value

Returns a collection of application elements (servers, OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElement).
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 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 discovery services on specified discovery endpoints.

Invokes the FindServers service.

The discovery may be attempted in parallel on the specified endpoints, depending on component settings.

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

When the flat parameter is false, the discovery query returns one OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElement for each application found, and its OpcLabs.EasyOpc.UA.Discovery.IUAReadOnlyApplicationElement.DiscoveryUriStrings property contains one or more application discovery URLs.

When the flat parameter is true, the discovery query returns one OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElement for each discovery URL of each application found. In this case, the OpcLabs.EasyOpc.UA.Discovery.IUAReadOnlyApplicationElement.DiscoveryUriStrings property of each returned application element contains precisely one string, and you can therefore use the OpcLabs.EasyOpc.UA.Discovery.IUAReadOnlyApplicationElement.DiscoveryUriString property instead to obtain the discovery URL.

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