SWbemServices.SubclassesOfAsync method

Article
01/07/2021

The SubclassesOfAsync method of the SWbemServices object returns a collection of subclasses for a specified class. Only use this method for class objects.

This method is called in the asynchronous mode. For more information, see Calling a Method.

For an explanation of this syntax, see Document Conventions for the Scripting API.

Syntax

SWbemServices.SubclassesOfAsync( _
  ByVal ObjWbemSink, _
  [ ByVal strSuperclass ], _
  [ ByVal iFlags ], _
  [ ByVal objwbemNamedValueSet ], _
  [ ByVal objWbemAsyncContext ] _
)

Parameters

ObjWbemSink: Required. Object sink that receives the subclasses asynchronously. Create a SWbemSink object to receive the objects.
strSuperclass [optional]: Specifies a parent class name. Only the classes that are subclasses of this class are returned in the enumerator. If this parameter is blank, and if iFlags is wbemQueryFlagShallow, only the top-level classes are returned (that is, classes that have no parent class). If this parameter is blank, and if iFlags is wbemQueryFlagDeep, all classes within the namespace are returned.
iFlags [optional]: Determines the depth of the call enumeration. The default value for this parameter is wbemQueryFlagDeep. This parameter can accept the following values.
wbemQueryFlagShallow (1 (0x1)): Forces the enumeration to include only immediate subclasses of the specified parent class.
wbemQueryFlagDeep (0 (0x0)): Default for this parameter. This value forces recursive enumeration into all subclasses that are derived from the specified parent class. The parent class is not returned in the enumeration.
wbemFlagSendStatus (128 (0x80)): Causes asynchronous calls to send status updates to the OnProgress event handler for the object sink.
wbemFlagDontSendStatus (0 (0x0)): Prevents asynchronous calls from sending status updates to the OnProgress event handler for the object sink.
wbemFlagUseAmendedQualifiers (131072 (0x20000)): Causes WMI to return class amendment data with the base class definition. For more information, see Localizing WMI Class Information.

objwbemNamedValueSet [optional]

Typically, this parameter is undefined. Otherwise, this is an SWbemNamedValueSet object whose elements represent the context information that can be used by the provider that is servicing the request. A provider that supports or requires such information must document the recognized value names, data type of the value, allowed values, and semantics.

objWbemAsyncContext [optional]

An SWbemNamedValueSet object that returns to the object sink to identify the source of the original asynchronous call. Use this parameter to make multiple asynchronous calls using the same object sink. To use this parameter, create an SWbemNamedValueSet object and use the SWbemNamedValueSet.Add method to add a value that identifies the asynchronous call you are making. This SWbemNamedValueSet object is returned to the object sink and the source of the call can be extracted using the SWbemNamedValueSet.Item method. For more information, see Calling a Method.

Return value

This method does not return a value. If successful, the sink receives an OnObjectReady event per instance. After the last instance, the object sink receives an OnCompleted event.

Error codes

After the completion of the SubclassesOfAsync method, the Err object may contain one of the error codes in the following list.

Note

A returned collection with zero elements is not an error.

wbemErrAccessDenied - 2147749891 (0x80041003): Current user does not have the permission to view one or more of the classes returned by the call.
wbemErrFailed - 2147749889 (0x80041001): Unspecified error.
wbemErrInvalidClass - 2147749904 (0x80041010): Specified class does not exist.
wbemErrInvalidParameter - 2147749896 (0x80041008): Invalid parameter was specified.
wbemErrOutOfMemory - 2147749894 (0x80041006): Not enough memory to complete the operation.

Remarks

This call returns immediately. The requested objects and status are returned to the caller through callbacks delivered to the sink that is specified in objWbemSink. To process each object when it arrives, create an objWbemSink.OnObjectReady event subroutine. After all the objects are returned, you can perform the final processing in your implementation of the objWbemSink.OnCompleted event.

An asynchronous callback allows a non-authenticated user to provide data to the sink. This poses security risks to your scripts and applications. To eliminate the risks, see Setting Security on an Asynchronous Call.

Requirements

Requirement	Value
Minimum supported client	Windows Vista
Minimum supported server	Windows Server 2008
Header	Wbemdisp.h
Type library	Wbemdisp.tlb
DLL	Wbemdisp.dll
CLSID	CLSID_SWbemServices
IID	IID_ISWbemServices