SWbemServices.ReferencesToAsync method

Makale
01/07/2021

The ReferencesToAsync method of the SWbemServices object returns all association classes or instances that refer to a specific source class or instance. This method performs the same function that the REFERENCES OF WQL query performs.

For more information about the asynchronous mode, see Calling a Method.

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

Syntax

SWbemServices.ReferencesToAsync( _
  ByVal ObjWbemSink, _
  ByVal strObjectPath, _
  [ ByVal strResultClass ], _
  [ ByVal strRole ], _
  [ ByVal bClassesOnly ], _
  [ ByVal bSchemaOnly ], _
  [ ByVal strRequiredQualifier ], _
  [ ByVal iFlags ], _
  [ ByVal objWbemNamedValueSet ], _
  [ ByVal objWbemAsyncContext ] _
)

Parameters

ObjWbemSink: Required. Object sink that receives the objects asynchronously. Create a SWbemSink object to receive the objects.
strObjectPath: Required. String that contains the object path of the source for this method. For more information, see Localizing WMI Class Information.
strResultClass [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 that is specified in this parameter.
strRole [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 role is defined by the name of a specified reference property of an association.
bClassesOnly [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 [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 strObjectPath parameter specifies the object path of a class. When set to TRUE, the set of returned endpoints represents classes that are associated with the source class in schema.
strRequiredQualifier [optional]: String that contains a qualifier name. If specified, this parameter indicates that the returned association objects must include the specified qualifier.
iFlags [optional]: Integer that specifies additional flags to the operation. The default for this parameter is wbemFlagBidirectional. This parameter can accept the following values.
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 Windows Management Instrumentation (WMI) to return class amendment data along with the base class definition. For more information, see Localizing WMI Class Information.

objWbemNamedValueSet [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 context information must document the recognized value names, data type of the value, allowed values, and semantics.

objWbemAsyncContext [optional]

This is 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 ReferencesToAsync 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.
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 returns, 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, 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

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