加载网络图片并显示 OleLoadPicture没取到值

[phhui]

代码如下：
断点到代码中标的地方停了，不知道是什么问题，刚接触C++一时找不到解决方法，这是什么原因？或我要怎么处理这个问题？

HDC hDC_Temp = dc->GetSafeHdc();
	IPicture *pPic;
	IStream *pStm;
	HRESULT bResult;// = FALSE;        
	DWORD dwFileSize, dwByteRead;
	//读取网页上图片文件，实际是个CHttpFile指针    
	CInternetSession session(L"HttpClient");
	CFile* httpFile = (CFile*)session.OpenURL(url);
	if (httpFile != INVALID_HANDLE_VALUE){
		dwFileSize = httpFile->GetLength();//获取文件字节数        
		if (dwFileSize == 0xFFFFFFFF)
			return E_FAIL;
	}else{
		return E_FAIL;
	}
	//分配全局存储空间        
	HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, dwFileSize);
	LPVOID pvData = NULL;
	if (hGlobal == NULL)
		return E_FAIL;

	if ((pvData = GlobalLock(hGlobal)) == NULL)//锁定分配内存块        
		return E_FAIL;

	//把文件读入内存缓冲区        
	dwByteRead = httpFile->Read(pvData, dwFileSize);
	GlobalUnlock(hGlobal);
	CreateStreamOnHGlobal(hGlobal, TRUE, &pStm);
	//装入图形文件        
	bResult = OleLoadPicture(pStm, dwFileSize, TRUE, IID_IPicture, (LPVOID*)&pPic);
	if (FAILED(bResult))
		return E_FAIL;//*****【【【【【------到这里停止了------】】】】】******

	OLE_XSIZE_HIMETRIC hmWidth; //图片的真实宽度, 单位为英寸       
	OLE_YSIZE_HIMETRIC hmHeight; //图片的真实高度, 单位为英寸       
	pPic->get_Width(&hmWidth);
	pPic->get_Height(&hmHeight);
	//转换hmWidth和hmHeight为pixels距离，1英寸=25.4毫米       
	int nWidth = MulDiv(hmWidth, GetDeviceCaps(hDC_Temp, LOGPIXELSX), 2540);
	int nHeight = MulDiv(hmHeight, GetDeviceCaps(hDC_Temp, LOGPIXELSY), 2540);

	//缩放图片
	int nWZoom = nWidth / rect.Width();
	int nHZoom = nHeight / rect.Height();
	int nZoom = 1;
	nZoom = (nWZoom > nHZoom) ? nWZoom : nHZoom;
	nWidth /= nZoom;
	nHeight /= nZoom;
	int midW = (rect.left + rect.right) / 2;
	int midH = (rect.top + rect.bottom) / 2;
	rect.left = midW - nWidth / 2;
	rect.right = midW + nWidth / 2;
	rect.top = midH - nHeight / 2;
	rect.bottom = midH + nHeight / 2;
	//将图形输出到屏幕上（有点像BitBlt）        
	bResult = pPic->Render(hDC_Temp, rect.left, rect.top, rect.Width(), rect.Height(),0, hmHeight, hmWidth, -hmHeight, NULL);
	pPic->Release();
	httpFile->Close();//关闭打开的文件        
	if (SUCCEEDED(bResult)){
		return S_OK;
	}else{
		return E_FAIL;
	}

[赵4老师]

OleLoadPicture Creates a new picture object and initializes it from the contents of a stream. This is equivalent to calling OleCreatePictureIndirect(NULL, ...) followed by IPersistStream::Load. STDAPI OleLoadPicture( IStream * pStream, //Pointer to the stream that contains picture's data LONG lSize, //Number of bytes read from the stream BOOL fRunmode, //The opposite of the initial value of the picture's // property REFIID riid, //Reference to the identifier of the interface // describing the type of interface pointer to return VOID ppvObj //Address of output variable that receives interface // pointer requested in riid ); Parameters pStream [in] Pointer to the stream that contains the picture's data. lSize [in] Number of bytes that should be read from the stream, or zero if the entire stream should be read. fRunmode [in] The opposite of the initial value of the KeepOriginalFormat property. If TRUE, KeepOriginalFormat is set to FALSE and vice-versa. riid [in] Reference to the identifier of the interface describing the type of interface pointer to return in ppvObj. ppvObj [out] Address of pointer variable that receives the interface pointer requested in riid. Upon successful return, *ppvObj contains the requested interface pointer on the storage of the object identified by the moniker. If *ppvObj is non-NULL, this function calls IUnknown::AddRef on the interface; it is the caller's responsibility to call IUnknown::Release. If an error occurs, *ppvObj is set to NULL. Return Values This function supports the standard return values E_OUTOFMEMORY and E_UNEXPECTED, as well as the following: S_OK The picture was created successfully. E_POINTER The address in pStream or ppvObj is not valid. For example, either may be NULL. E_NOINTERFACE The object does not support the interface specified in riid. Remarks The stream must be in BMP (bitmap), WMF (metafile), or ICO (icon) format. A picture object created using OleLoadPicture always has ownership of its internal resources (fOwn==TRUE is implied). QuickInfo Windows NT: Use version 4.0 or later. Windows: Use Windows 95 or later. Windows CE: Unsupported. Header: Declared in olectl.h. Import Library: Included as a resource in olepro32.dll. See Also OleCreatePictureIndirect, PICTDESC

[cutmelon]

GlobalUnlock(hGlobal);过早