QuickOPC User's Guide and Reference
QueryCategoryAttributes(IEasyAEClient,String,String,Int64) Method



OpcLabs.EasyOpcClassic Assembly > OpcLabs.EasyOpc.AlarmsAndEvents Namespace > IEasyAEClientExtension Class > QueryCategoryAttributes Method : QueryCategoryAttributes(IEasyAEClient,String,String,Int64) Method
The client object that will perform the operation.
Name of the machine. Determines the computer on which the OPC server is located. May be an empty string, in which case the OPC server is assumed to exist on the local computer or at the computer specified for it by DCOM configuration.
Contains ProgID of the OPC server.
An event category Id for which the event attributes should be queried.
Finds out event attributes that the server can provide as part of an event notification within a given event category. Uses computer name and server class for specifying the OPC server.
Syntax
'Declaration
 
<ExtensionAttribute()>
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function QueryCategoryAttributes( _
   ByVal client As IEasyAEClient, _
   ByVal machineName As String, _
   ByVal serverClass As String, _
   ByVal categoryId As Long _
) As AEAttributeElementCollection
'Usage
 
Dim client As IEasyAEClient
Dim machineName As String
Dim serverClass As String
Dim categoryId As Long
Dim value As AEAttributeElementCollection
 
value = IEasyAEClientExtension.QueryCategoryAttributes(client, machineName, serverClass, categoryId)
[Extension()]
[ElementsNotNull()]
[NotNull()]
public static AEAttributeElementCollection QueryCategoryAttributes( 
   IEasyAEClient client,
   string machineName,
   string serverClass,
   long categoryId
)
[Extension()]
[ElementsNotNull()]
[NotNull()]
public:
static AEAttributeElementCollection^ QueryCategoryAttributes( 
   IEasyAEClient^ client,
   String^ machineName,
   String^ serverClass,
   int64 categoryId
) 

Parameters

client
The client object that will perform the operation.
machineName
Name of the machine. Determines the computer on which the OPC server is located. May be an empty string, in which case the OPC server is assumed to exist on the local computer or at the computer specified for it by DCOM configuration.
serverClass
Contains ProgID of the OPC server.
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
ExceptionDescription
A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.
The OPC "Classic" (or OPC XML-DA) operation has failed.
The value of an argument is outside the allowable range of values as defined by the invoked method.
Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2012, Windows Server 2016; .NET Core, .NET 5, .NET 6: Linux, macOS, Microsoft Windows

See Also

Reference

IEasyAEClientExtension Class
IEasyAEClientExtension Members
Overload List