directX枚举系统设备类

void CSysEnumDlg::DisplayFullCategorySet(void)
{
USES_CONVERSION;

HRESULT hr;
IEnumMoniker *pEmCat = 0;
ICreateDevEnum *pCreateDevEnum = NULL;
int nClasses=0;

// Create an enumerator
hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,
IID_ICreateDevEnum, (void**)&pCreateDevEnum);
ASSERT(SUCCEEDED(hr));
if (FAILED(hr))
return;

// Use the meta-category that contains a list of all categories.
// This emulates the behavior of GraphEdit.
hr = pCreateDevEnum->CreateClassEnumerator(
CLSID_ActiveMovieCategories, &pEmCat, 0);
ASSERT(SUCCEEDED(hr));

if(hr == S_OK)
{
IMoniker *pMCat;
ULONG cFetched;

// Enumerate over every category
while(hr = pEmCat->Next(1, &pMCat, &cFetched),
hr == S_OK)
{
IPropertyBag *pPropBag;

// Associate moniker with a file
hr = pMCat->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pPropBag);
if(SUCCEEDED(hr))
{
VARIANT varCatClsid;
varCatClsid.vt = VT_BSTR;

// Read CLSID string from property bag
hr = pPropBag->Read(L"CLSID", &varCatClsid, 0);
if(SUCCEEDED(hr))
{
CLSID clsidCat;//枚举所有的设备类

if(CLSIDFromString(varCatClsid.bstrVal, &clsidCat) == S_OK)
{
// Use the guid if we can't get the name
WCHAR *wszCatName;
TCHAR szCatDesc[MAX_PATH];

VARIANT varCatName;
varCatName.vt = VT_BSTR;

// Read filter name
hr = pPropBag->Read(L"FriendlyName", &varCatName, 0);
if(SUCCEEDED(hr))
wszCatName = varCatName.bstrVal;
else
wszCatName = varCatClsid.bstrVal;

#ifndef UNICODE
WideCharToMultiByte(
CP_ACP, 0, wszCatName, -1,
szCatDesc, sizeof(szCatDesc), 0, 0);
#else
lstrcpy(szCatDesc, W2T(wszCatName));
#endif

if(SUCCEEDED(hr))
SysFreeString(varCatName.bstrVal);

// Add category name and CLSID to list box
AddFilterCategory(szCatDesc, &clsidCat);
nClasses++;
}

SysFreeString(varCatClsid.bstrVal);
}

pPropBag->Release();
}
else
{
break;
}

pMCat->Release();
} // for loop

pEmCat->Release();
}

pCreateDevEnum->Release();

// Update listbox title with number of classes
SetNumClasses(nClasses);
}

巴特西

directX枚举系统设备类

最新文章

热门文章