OleLoad

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

HRESULT OleLoad(

IStorage * pStg,	//Points to the storage object from which to load
REFIID riid,	//Interface to use for the object being loaded
IOleClientSite * pClientSite,	//Points to the client site for the object
LPVOID * ppvObj	//Points to the newly loaded object
);

Parameters

pStg

Points to the storage object from which to load the specified object.

riid

Specifies the interface that the caller wants to use when talking to the object once it is loaded.

pClientSite

Points to the client site for the object being loaded.

ppvObj

Points to the newly loaded object.

Return Values

S_OK

Indicates the object was loaded successfully.

E_OUTOFMEMORY

Indicates the object could not be loaded due to lack of memory.

E_NOINTERFACE

Indicates the object does not support the specified interface.

See also the IPersistStorage::Load method for other error return values.

Comments

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

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