我用BCB6寫一個可以選擇Capture Device的程式（如下）      IGraphBuilder *pGraph;   ICaptureGraphBuilder2 *pBuild;      // Create the Capture Graph Builder.   HRESULT hr = CoCreateInstance(CLSID_CaptureGraphBuilder2, NULL,    CLSCTX_INPROC_SERVER, IID_ICaptureGraphBuilder2, (void**)&pBuild);   if (SUCCEEDED(hr))   {     // Create the Filter Graph Manager.     hr = CoCreateInstance(CLSID_FilterGraph, 0, CLSCTX_INPROC_SERVER, IID_IGraphBuilder, (void**)&pGraph);     if (SUCCEEDED(hr))     {       // Initialize the Capture Graph Builder.       pBuild->SetFiltergraph(pGraph);     }     else     {       pBuild->Release();     }     ICreateDevEnum *pDevEnum = NULL;     IEnumMoniker *pEnum = NULL;        // Create the System Device Enumerator.     hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, reinterpret_cast(&pDevEnum)); if (SUCCEEDED(hr)) { // Create an enumerator for the video capture category. hr = pDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory, &pEnum, 0); IMoniker *pMoniker; while (pEnum->Next(1, &pMoniker, NULL) == S_OK) { IPropertyBag *pPropBag; hr = pMoniker->BindToStorage(0, 0, IID_IPropertyBag, (void**)(&pPropBag)); if (FAILED(hr)) { pMoniker->Release(); continue; // Skip this one, maybe the next one will work. } // Find the description or friendly name. VARIANT varName; VariantInit(&varName); hr = pPropBag->Read(L"Description", &varName, 0); if (FAILED(hr)) { hr = pPropBag->Read(L"FriendlyName", &varName, 0); } if (SUCCEEDED(hr)) { DevList->Items->Add(VarToStr(&varName)); } pPropBag->Release(); pMoniker->Release(); } } } 但在按Run後在 while (pEnum->Next(1, &pMoniker, NULL) == S_OK) 會出現 EAccess Violation 的錯誤訊息，請問各位高手可否指點一下。