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OleDoAutoConvert function

Automatically converts an object to a new class if automatic conversion for that object class is set in the registry.

Syntax


HRESULT OleDoAutoConvert(
  _In_   LPSTORAGE pStg,
  _Out_  LPCLSID pClsidNew
);

Parameters

pStg [in]

A pointer to the IStorage interface on the storage object to be converted.

pClsidNew [out]

A pointer to the new CLSID for the object being converted. If there was no automatic conversion, this may be the same as the original class.

Return value

This function can return the standard return values E_INVALIDARG, E_OUTOFMEMORY, and E_UNEXPECTED, as well as the following values.

Return codeDescription
S_OK

No conversion is needed or a conversion was successfully completed.

REGDB_E_KEYMISSING

The function cannot read a key from the registry.

 

This function can also return any of the error values returned by the OleGetAutoConvert function. When accessing storage and stream objects, see the IStorage::OpenStorage and IStorage::OpenStream methods for possible errors. When it is not possible to determine the existing CLSID or when it is not possible to update the storage object with new information, see the IStream interface for other error return values.

Remarks

OleDoAutoConvert automatically converts an object if automatic conversion has previously been specified in the registry by the OleSetAutoConvert function. Object conversion means that the object is permanently associated with a new CLSID. Automatic conversion is typically specified by the setup program for a new version of an object application, so that objects created by its older versions can be automatically updated.

The storage object must be in the unloaded state when OleDoAutoConvert is called.

A container application that supports object conversion should call OleDoAutoConvert each time it loads an object. If the container uses the OleLoad helper function, it need not call OleDoAutoConvert explicitly because OleLoad calls it internally.

OleDoAutoConvert first determines whether any conversion is required by calling the OleGetAutoConvert function, which, if no conversion is required, returns S_OK. If the object requires conversion, OleDoAutoConvert modifies and converts the storage object by activating the new object application. The new object application reads the existing data format, but saves the object in the new native format for the object application.

If the object to be automatically converted is an OLE 1 object, the ItemName string is stored in a stream called "\1Ole10ItemName." If this stream does not exist, the object's item name is NULL.

Requirements

Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]

Header

Ole2.h

Library

Ole32.lib

DLL

Ole32.dll

See also

OleGetAutoConvert
OleSetAutoConvert

 

 

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