Lets you specify a particular IID If your object supports multiple dispatch interfaces. Resembles PROP_ENTRY_INTERFACE.
PROP_ENTRY_INTERFACE_EX( szDesc, dispid, clsid, iidDispatch, rgclsidAllowed, cclsidAllowed, vt )
Include this macro to give an application more control over the IPersistStreamInitImpl::Load process. This macro only applies if IPersistStreamInitImpl is a base class and the class is advertised as safe for initializing. Otherwise, you should not use this macro.
In most cases, cclsidAllowed can be determined by _countof(rgclsidAllowed).
This macro is only valid if vt is VT_DISPATCH or VT_UNKNOWN. Passing in a different value for vt to this macro will cause a compilation error. For any other value of vt, use PROP_ENTRY_TYPE_EX.
If you are creating a web control that needs to be initialized, you should use the IPersistPropertyBagImpl Class instead of IPersistStreamInitImpl to initialize properties. IPersistStreamInitImpl possess a greater risk in binary format than IPersistPropertyBagImpl.