IDispatchImpl Class (ATL)

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ATL Library Reference

IDispatchImpl Class

This class provides a default implementation for IDispatch portion of a dual interface.

template<
   class T,
   const IID* piid= &__uuidof(T),
   const GUID* plibid = &CAtlModule::m_libid,
   WORD wMajor = 1,
   WORD wMinor = 0,
   class tihclass = CComTypeInfoHolder 
> 
class ATL_NO_VTABLE IDispatchImpl :
   public T

Parameters

T: A dual interface.

piid: A pointer to the IID of T.

plibid: A pointer to the LIBID of the type library that contains information about the interface. By default, the server-level type library is passed.

wMajor: The major version of the type library. The default value is 1.

wMinor: The minor version of the type library. The default value is 0.

tihclass: The class used to manage the type information for T. The default value is CComTypeInfoHolder.

Remarks

IDispatchImpl provides a default implementation for the IDispatch portion of any dual interface on your object. A dual interface derives from IDispatch and uses only Automation-compatible types. Like a dispinterface, a dual interface supports early and late binding; however, a dual interface differs in that it also supports vtable binding. For more information, see Implementing the IDispatch Interface.

The following example shows a typical implementation of IDispatchImpl:

class CBeeper :
      public IDispatchImpl< IBeeper, &IID_IBeeper, 
         &LIBID_BeeperLib >,
      public CComObjectRoot,
      public CComCoClass< CBeeper, &CLSID_Beeper >
{
   ...
};

IDispatchImpl contains a static member of type CComTypeInfoHolder that manages the type information for the dual interface. If you have multiple objects implementing the same dual interface, only a single instance of CComTypeInfoHolder will be used.

Requirements

Header: atlcom.h

Other Resources

IDispatchImpl Members
ATL Class Overview