CreateStdDispatch

(punkOuter, pvThis, ptinfo, ppunkStdDisp)
IUnknown FAR* punkOuter
void FAR* pvThis
ITypeInfo FAR* ptinfo
IUnknown FAR* FAR* ppunkStdDisp

Creates a standard implementation of the IDispatch interface through a single function call. This simplifies exposing objects through OLE Automation.

Parameters

punkOuter

Pointer to the object's IUnknown implementation.

pvThis

Pointer to the object to expose.

ptinfo

Pointer to the type information that describes the exposed object.

ppunkStdDisp

Pointer to the location where the implementation of the IDispatch interface for this object is returned. This pointer is NULL if the function fails.

Return Value

The SCODE obtained from the returned HRESULT is one of the following:

SCODE	Meaning
S_OK	Success.
E_INVALIDARG	One of the first three arguments is invalid.
E_OUTOFMEMORY	There was insufficient memory to complete the operation.

Comments

You can use CreateStdDispatch when you create an object instead of implementing the IDispatch member functions for the object. The implementation that CreateStdDispatch creates has these limitations:

• Supports only one national language

• Supports only dispatch-defined exception codes returned from Invoke

LoadTypeLib, GetTypeInfoOfGuid, and CreateStdDispatch comprise the minimum set of functions you need to cal l to expose an object using a type library. For more information on LoadTypeLib and GetTypeInfoOfGuid, see Chapter 8, "Type Description Interfaces."

CreateDispTypeInfo and CreateStdDispatch comprise the minimum set of dispatch components you need to call to expose an object using type information provided by the INTERFACEDATA structure.

Example

The following code implements the IDispatch interface for the CCalc class using CreateStdDispatch.

CCalc FAR*

CCalc::Create()

{

HRESULT hresult;

CCalc FAR* pcalc;

CArith FAR* parith;

ITypeInfo FAR* ptinfo;

IUnknown FAR* punkStdDisp;

extern INTERFACEDATA NEARDATA g_idataCCalc;

if((pcalc = new FAR CCalc()) == NULL)

return NULL;

pcalc->AddRef();

parith = &(pcalc->m_arith);

// Build a TypeInfo for the functionality on this object that

// is being exposing for external programmability.

hresult = CreateDispTypeInfo(

&g_idataCCalc, LOCALE_SYSTEM_DEFAULT, &ptinfo);

if(hresult != NOERROR)

goto LError0;

// Create an aggregate with an instance of the default

// implementation of IDispatch that is initialized with our

// TypeInfo.

hresult = CreateStdDispatch(

pcalc, // controlling unknown

parith, // instance to dispatch on

ptinfo, // typeinfo describing the instance

&punkStdDisp);

ptinfo->Release();

if(hresult != NOERROR)

goto LError0;

pcalc->m_punkStdDisp = punkStdDisp;

return pcalc;

LError0:;

pcalc->Release();

return NULL;

}

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