CreateDispTypeInfo

HRESULT CreateDispTypeInfo( 
  INTERFACEDATA  pidata,        
  LCID  lcid,                   
  ITypeInfo FAR* FAR*  pptinfo  
);
 

Creates simplified type information for use in an implementation of IDispatch.

Parameters

pidata

The interface description that this type information describes.

lcid

The locale identifier for the names used in the type information.

pptinfo

On return, pointer to a type information implementation for use in DispGetIDsOfNames and DispInvoke.

Return Value

The return value obtained from the returned HRESULT is one of the following:

Comments

You can construct type information at run time by using CreateDispTypeInfo and an INTERFACEDATA structure that describes the object being exposed.

The type information returned by this function is primarily designed to automate the implementation of IDispatch. CreateDispTypeInfo does not return all of the type information described in Chapter 9, "Type Description Interfaces." The argument pidata is not a complete description of an interface. It does not include Help information, comments, optional parameters, and other type information that is useful in different contexts.

Accordingly, the recommended method for providing type information about an object is to describe the object using the Object Description Language (ODL), and to compile the object description into a type library using the Microsoft Interface Definition Language (MIDL) compiler or the MkTypLib utility.

To use type information from a type library, use the LoadTypeLib and GetTypeInfoOfGuid functions instead of CreateDispTypeInfo. For more information, see Chapter 9, "Type Description Interfaces."

Example

The code that follows creates type information from INTERFACEDATA to expose the CCalc object.

static METHODDATA NEARDATA rgmdataCCalc[] =
{
        PROPERTY(VALUE,  IMETH_ACCUM,    IDMEMBER_ACCUM,    VT_I4)
        PROPERTY(ACCUM,  IMETH_ACCUM,    IDMEMBER_ACCUM,    VT_I4)
        PROPERTY(OPND,   IMETH_OPERAND,  IDMEMBER_OPERAND,  VT_I4)
        PROPERTY(OP,     IMETH_OPERATOR, IDMEMBER_OPERATOR, VT_I2)
        METHOD0(EVAL,    IMETH_EVAL,     IDMEMBER_EVAL,     VT_BOOL)
        METHOD0(CLEAR,   IMETH_CLEAR,    IDMEMBER_CLEAR,    VT_EMPTY)
        METHOD0(DISPLAY, IMETH_DISPLAY,  IDMEMBER_DISPLAY,  VT_EMPTY)
        METHOD0(QUIT,    IMETH_QUIT,     IDMEMBER_QUIT,     VT_EMPTY)
        METHOD1(BUTTON,  IMETH_BUTTON,   IDMEMBER_BUTTON,   VT_BOOL)
};

INTERFACEDATA NEARDATA g_idataCCalc =
{
    rgmdataCCalc, DIM(rgmdataCCalc)
};

// Use Dispatch interface API functions to implement IDispatch.
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 type information for the functionality on this object that
    // is being exposed 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 
    // type information.
    hresult = CreateStdDispatch(
        pcalc,                // Controlling unknown.
        parith,                // Instance to dispatch on.
        ptinfo,                // Type information describing the instance.
        &punkStdDisp);

    ptinfo->Release();

    if(hresult != NOERROR)
        goto LError0;

    pcalc->m_punkStdDisp = punkStdDisp;

    return pcalc;

LError0:;
    pcalc->Release();
    return NULL;
}

QuickInfo

  Windows NT: Use version 3.1 and later.
  Windows: Use Windows 95 and later.
  Header: Declared in oleauto.h.
  Import Library: Link with oleaut32.lib.