exe导出的hIcon 怎样转化为透明背景的hBitmap？

 
         HICON hIconLarge; ExtractIconEx(strPath, 0, &hIconLarge, NULL, 1); Gdiplus::Bitmap* pBitmap = Gdiplus::Bitmap::FromHICON(hIconLarge); //Gdiplus::Color color = Gdiplus::Color::Transparent; pBitmap->GetHBITMAP(Gdiplus::Color::Transparent, &hBitmap); //释放icon句柄
if(hIconLarge)
DestroyIcon(hIconLarge); //无图标则使用默认图标
if(hBitmap != NULL)
pSWIcon->SetImageHandle((OLE_HANDLE)HandleToLong(hBitmap));
else
pSWIcon->SetLogoImage(_T("Icon\\logodef.ico"));
       上面是代码，我得到exe中图标句柄HICON，然后转化为HBITMAP, 背景色无法变成透明色，Gdiplus::Color::Transparent 好像不起作用。怎样做才能得到透明HBITMAP?