QueryCategoryAttributes(IEasyAEClient,ServerDescriptor,Int64) Method

Finds out event attributes that the server can provide as part of an event notification within a given event category. Uses server descriptor for specifying the OPC server.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function QueryCategoryAttributes( _
   ByVal client As IEasyAEClient, _
   ByVal serverDescriptor As ServerDescriptor, _
   ByVal categoryId As Long _
) As AEAttributeElementCollection

'Usage
 
Dim client As IEasyAEClient
Dim serverDescriptor As ServerDescriptor
Dim categoryId As Long
Dim value As AEAttributeElementCollection
 
value = IEasyAEClientExtension.QueryCategoryAttributes(client, serverDescriptor, categoryId)

[Extension()]
[ElementsNotNull()]
[NotNull()]
public static AEAttributeElementCollection QueryCategoryAttributes( 
   IEasyAEClient client,
   ServerDescriptor serverDescriptor,
   long categoryId
)

[Extension()]
[ElementsNotNull()]
[NotNull()]
public:
static AEAttributeElementCollection^ QueryCategoryAttributes( 
   IEasyAEClient^ client,
   ServerDescriptor^ serverDescriptor,
   int64 categoryId
)

Parameters

client: The client object that will perform the operation.
serverDescriptor: The OPC server involved in the operation.
categoryId: An event category Id for which the event attributes should be queried.

Return Value

A collection of attribute elements, one element for each attribute of the given event category.

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.

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

IEasyAEClientExtension Class
IEasyAEClientExtension Members
Overload List

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