SWbemObject.ReferencesAsync_ method

Artikkeli
01/07/2021

The ReferencesAsync_ method of SWbemObject supplies a collection of all association classes or instances that refer to the current object. This method performs the same function that the WQL REFERENCES OF query performs.

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

Syntax

SWbemObject.ReferencesAsync_( _
  ByVal objWbemSink, _
  [ ByVal strResultClass ], _
  [ ByVal strRole ], _
  [ ByVal bClassesOnly ], _
  [ ByVal bSchemaOnly ], _
  [ ByVal strRequiredQualifier ], _
  [ ByVal iFlags ], _
  [ ByVal objwbemNamedValueSet ], _
  [ ByVal objWbemAsyncContext ] _
)

Parameters

objWbemSink [in]: Required. Object sink that receives the objects asynchronously.
strResultClass [in, optional]: String that contains a class name. If specified, this parameter indicates that the returned association objects must belong to or be derived from the class specified in this parameter.
strRole [in, optional]: String that contains a property name. If specified, this parameter indicates that the returned association objects must be limited to those in which the source object plays a specific role. The name of a specified reference property defines the role of an association.
bClassesOnly [in, optional]: Boolean value that indicates whether or not a list of class names should be returned rather than actual instances of the classes. These are the classes to which the association objects belong. The default value for this parameter is FALSE.
bSchemaOnly [in, optional]: Boolean value that indicates whether or not the query applies to the schema rather than the data. The default value for this parameter is FALSE. It can only be set to TRUE if the object on which this method is invoked is a class. When set to TRUE, the set of returned endpoints represents classes that are suitably associated with the source class in the schema.
strRequiredQualifier [in, optional]: String that contains a qualifier name. If specified, this parameter indicates that the returned association objects must include the specified qualifier.
iFlags [in, optional]: Integer specifying additional flags to the operation. This parameter can accept the following values.
wbemFlagSendStatus (128 (0x80)): Causes asynchronous calls to send status updates to the SWbemSink.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 Windows Management Instrumentation (WMI) to return class amendment data with the base class definition. For more information, see Localizing WMI Class Information.

objwbemNamedValueSet [in, optional]

Typically, this 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 [in, optional]

This is an SWbemNamedValueSet object that returns to the object sink to identify the source of the original asynchronous call. Use this parameter if you are making 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 ReferencesAsync_ method, the Err object may contain one of the error codes in the following list.

wbemErrAccessDenied - 2147749891 (0x80041003): Current user does not have permission to view one or more of the classes returned by the call.
wbemErrFailed - 2147749889 (0x80041001): Unspecified error.
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 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, use either semisynchronous communication or synchronous communication. For more information, see Calling a Method.

For more information about the REFERENCES OF associated WQL query, source instances, and association objects, see ASSOCIATORS OF Statement.

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_SWbemObject
IID	IID_ISWbemObject

Jaa