IPersistStream

The IPersistStream interface provides methods for saving and loading objects that use a simple serial stream for their storage needs. The primary purpose of this interface is to support OLE moniker implementations. Each of the OLE-provided moniker interfaces provide an IPersistStream implementation through which the moniker saves or loads itself. An instance of the OLE generic composite moniker class calls the IPersistStream methods of its component monikers to load or save the components in the proper sequence in a single stream.

OLE containers with embedded and linked component objects do not use this interface; they use the IPersistStorage interface instead.

When to Implement
Typically, applications do not implement the IPersistStream interface. However, the IMoniker interface is derived from the IPersistStream interface, so you must implement the IPersistStream interface if you are implementing a new moniker class.

When to Use
Typically, applications do not use the IPersistStream interface directly. The default link handler uses the IPersistStream interface to save and load the monikers that identify the link source. These monikers are stored in a stream in the storage for the linked object. If you are writing a custom link handler for your class of components, you will need to use the IPersistStream interface to load and save these monikers.

Methods in Vtable Order

IUnknown Methods	Description
QueryInterface	Returns pointers to supported interfaces.
AddRef	Increments the reference count.
Release	Decrements the reference count.

IPersistStream Methods	Description
IsDirty	Checks the object for changes since it was last saved.
Load	Initializes an object from the stream where it was previously saved.
Save	Saves an object into the specified stream and indicates whether the object should reset its dirty flag.
GetSizeMax	Return the size in bytes of the stream needed to save the object.