# OleLoad

Loads into memory an object nested within a specified storage object.

WINOLEAPI OleLoad(

IStorage * pStg, | //Pointer to the storage object from which to load
REFIID riid, | //Reference to the identifier interface
IOleClientSite * pClientSite, | //Pointer to the client site for the object
LPVOID * ppvObj | //Indirect pointer to the newly loaded object
); |

Parameters

pStg
  [in] Pointer to the IStorage interface on the storage object from which to load the specified object.
riid
  [in] Reference to the identifier of the interface that the caller wants to use to communicate with the object once it is loaded.
pClientSite
  [in] Pointer to the IOleClientSite interface on the client site object being loaded.
ppvObj
  [out] When successful, indirect pointer to the interface specified in riid on the newly loaded object.

Return Values

This function supports the standard return value E_OUTOFMEMORY, as well as the following:

S_OK
  The object was loaded successfully.
E_NOINTERFACE
  The object does not support the specified interface.

This function can return any of the error values returned by the IPersistStorage::Load method.

Remarks

OLE containers load objects into memory by calling this function. When calling the OleLoad function, the container application passes in a pointer to the open storage object in which the nested object is stored. Typically, the nested object to be loaded is a child storage object to the container’s root storage object. Using the OLE information stored with the object, the object handler (usually, the default handler) attempts to load the object. On completion of the OleLoad function, the object is said to be in the loaded state with its object application not running.

Some applications load all of the object’s native data. Containers often defer loading the contained objects until required to do so. For example, until an object is scrolled into view and needs to be drawn, it does not need to be loaded.

The OleLoad function performs the following steps:

1. If necessary, performs an automatic conversion of the object (see the OleDoAutoConvert function).

2. Gets the CLSID from the open storage object by calling the IStorage::Stat method.

3. Calls the CoCreateInstance function to create an instance of the handler. If the handler code is not available, the default handler is used (see the OleCreateDefaultHandler function).

4. Calls the IOleObject::SetClientSite method with the pClientSite parameter to inform the object of its client site.

5. Calls the QueryInterface method for the IPersistStorage interface. If successful, the IPersistStorage::Load method is invoked for the object.

6. Queries and returns the interface identified by the riid parameter.

See Also

ReadClassStg, IClassFactory::CreateInstance, IPersistStorage::Load