Using a Custom Interface

The client code is the user of the custom interface. To use any interface, custom or standard, a client must know its IID. In the following function, CustomRpt, the driver that calls CustomRpt passes it the name of the object that is converted to a wide-character format. The object name is fed to CreateFileMoniker so that a file moniker can be created and the client can bind to the running object. Once the object is running, CustomRpt can access a pointer to either an interface in the standard proxy/stub, such as IPersistFile, or to the custom interface, ICustomInterface.

• oid CustomRpt(char *pszObject)

{

HRESULT hr;

WCHAR szObject[128];

WCHAR wszMsg[128] = {L"Your Message Here...\n"};

IMoniker *pmkObject = NULL;

IUnknown *pIUnk = NULL;

IPersistFile *pIPersistFile = NULL;

ICustomInterface *pICustomInterface = NULL;

// Create a wide-character version of the object's file name.

wsprintf(wszObject, L"%hs", pszObject);

// Get a file moniker for the object (a *.smp file).

hr = CreateFileMoniker(wszObject, &pmkObject);

if(FAILED(hr))

{

printf("Client: CreateFileMoniker for Object failed");

return;

}

// BindMoniker is equivalent to calling CreateBindCtx() followed by

// a call to BindToObject(). It has the net result of binding the

// interface (specified by the IID) to the moniker.

hr = BindMoniker(pmkObject, 0, IID_IUnknown, (void **)&pIUnk);

if (FAILED(hr))

{

printf("Client: BindMoniker failed (%x)\n", hr);

return;

}

// Try a couple QueryInterface calls into the object code, first a

// QueryInterface to IPersistFile...

hr = pIUnk->QueryInterface(IID_IPersistFile,

(void **)&pIPersistFile);

if (FAILED(hr)) {

printf("Client: QueryInterface IPersistFile failed (%x)\n", hr);

pIUnk->Release();

return;

}

// Followed by a QueryInterface to ICustomInterface.

hr = pIUnk->QueryInterface(IID_ICustomInterface,

(void **)&pICustomInterface);

if (FAILED(hr)) {

printf("Client: QueryInterface failed (%x)\n", hr);

pIUnk->Release();

pIPersistFile->Release();

return;

}

// CustomReport() is the object function that displays the time and

// date information on the object.

hr = pICustomInterface->CustomReport();

if (FAILED(hr))

{

printf("Client: pICustomInterface->CustomReport failed (%x)\n",

hr);

pIUnk->Release();

pIPersistFile->Release();

return;

}

// Clean up resources by calling release on each of the interfaces.

pIPersistFile->Release();

pICustomInterface->Release();

pIUnk->Release();

return;

}

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