MFC通过系统API将指定窗口导出为图片，方法之一：

BOOL COutputManager::OutputFromWND(IN HWND hWnd, IN RECT rect)

{

HDC  hDC = ::GetDC(hWnd); //获取屏幕DC

HDC  hDCMem = ::CreateCompatibleDC(hDC); //创建兼容DC

HBITMAP  hBitMap = ::CreateCompatibleBitmap(hDC, rect.right, rect.bottom); //创建兼容位图

HBITMAP  hOldMap = ( HBITMAP )::SelectObject(hDCMem, hBitMap); //将位图选入DC，并保存返回值

::BitBlt(hDCMem, 0, 0, rect.right, rect.bottom, hDC, 0, 0, SRCCOPY); //将屏幕DC的图象复制到内存DC中

CImage image;

image.Attach(hBitMap);

image.Save(_T( "c://YMDownloads//output.jpg" ));//如果文件后缀为.bmp，则保存为为bmp格式

image.Detach();

::SelectObject(hDCMem, hOldMap); //选入上次的返回值

//释放

::DeleteObject(hBitMap);

::DeleteDC(hDCMem);

::DeleteDC(hDC);

return TRUE;

}