MFC 屏幕截图

void CDlgPrintScreen::OnBtnPrintScreen() 
{
	// TODO: Add your control notification handler code here
	// TODO: Add your control notification handler code here
AfxGetMainWnd()->ShowWindow(SW_MINIMIZE );
	Sleep(500);

	HWND hWnd = ::GetDesktopWindow();//获得屏幕的HWND.
	HDC hScreenDC = ::GetDC(hWnd);   //获得屏幕的HDC.
	HDC MemDC = ::CreateCompatibleDC(hScreenDC);
	RECT rect; 
	::GetWindowRect(hWnd,&rect);
	SIZE screensize;
	screensize.cx=rect.right-rect.left;
	screensize.cy=rect.bottom-rect.top;
	HBITMAP hBitmap = ::CreateCompatibleBitmap(hScreenDC,screensize.cx,screensize.cy);
	HGDIOBJ hOldBMP = ::SelectObject(MemDC,hBitmap);
	::BitBlt(MemDC,0,0,screensize.cx,screensize.cy,hScreenDC,rect.left,rect.top,SRCCOPY);
	::SelectObject(MemDC,hOldBMP);
	::DeleteObject(MemDC);
	::ReleaseDC(hWnd,hScreenDC);


//	if(this->m_bSaveToFile)
		this->WriteBmpToFile(hBitmap);
	
//	if(this->m_bCopyToClip)
		this->CopyBmpToClipBoard(hBitmap);

//	if(this->m_bOpenMspaint)
		::ShellExecute(NULL,"open","mspaint.exe",/*调用画图程序*/
			this->m_str_save_path,
			NULL,
			SW_SHOWMAXIMIZED);

	AfxGetMainWnd()->ShowWindow(SW_NORMAL);     //恢复窗口显示模式 
}

void CDlgPrintScreen::WriteBmpToFile(HBITMAP hBitmap)
{
HDC hDC =::CreateDC("DISPLAY",NULL,NULL,NULL); 
    int iBits = ::GetDeviceCaps(hDC, BITSPIXEL) * ::GetDeviceCaps(hDC, PLANES);//当前分辨率下每个像素所占字节数  
    ::DeleteDC(hDC);

    WORD   wBitCount;   //位图中每个像素所占字节数    
    if (iBits <= 1)
		wBitCount = 1;
    else if (iBits <= 4)
		wBitCount = 4;
    else if (iBits <= 8)
		wBitCount = 8;
    else if (iBits <= 24)
		wBitCount = 24;
    else
		wBitCount = iBits;
		    
	DWORD   dwPaletteSize=0;	//调色板大小， 位图中像素字节大小 
    if (wBitCount <= 8)		
		dwPaletteSize = (1 << wBitCount) *	sizeof(RGBQUAD);	
	

	BITMAP  bm;        //位图属性结构
    ::GetObject(hBitmap, sizeof(bm), (LPSTR)&bm);  

    
	BITMAPINFOHEADER   bi;       //位图信息头结构     
	bi.biSize            = sizeof(BITMAPINFOHEADER);  
    bi.biWidth           = bm.bmWidth;
    bi.biHeight          = bm.bmHeight;
    bi.biPlanes          = 1;
    bi.biBitCount        = wBitCount;
    bi.biCompression     = BI_RGB; //BI_RGB表示位图没有压缩
    bi.biSizeImage       = 0;
    bi.biXPelsPerMeter   = 0;
    bi.biYPelsPerMeter   = 0;
    bi.biClrUsed         = 0;
    bi.biClrImportant    = 0;
	
    DWORD dwBmBitsSize = ((bm.bmWidth * wBitCount+31)/32) * 4 * bm.bmHeight;    
    HANDLE hDib  = ::GlobalAlloc(GHND,dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));  //为位图内容分配内存
    LPBITMAPINFOHEADER lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
    *lpbi = bi;
	
    HANDLE hPal = ::GetStockObject(DEFAULT_PALETTE);  // 处理调色板 
	HANDLE  hOldPal=NULL; 
    if (hPal)
    {
		hDC = ::GetDC(NULL);
		hOldPal = SelectPalette(hDC,(HPALETTE)hPal, FALSE);
		RealizePalette(hDC);
    }
    ::GetDIBits(hDC, hBitmap, 0, (UINT) bm.bmHeight,(LPSTR)lpbi + sizeof(BITMAPINFOHEADER)+dwPaletteSize,(BITMAPINFO*)lpbi,DIB_RGB_COLORS);// 获取该调色板下新的像素值
    if (hOldPal)//恢复调色板
    {
		SelectPalette(hDC, (HPALETTE)hOldPal, TRUE);
		RealizePalette(hDC);
		::ReleaseDC(NULL, hDC);
    }	
   
	BITMAPFILEHEADER   bmfHdr; //位图文件头结构     
	bmfHdr.bfType = 0x4D42;  // "BM"  	// 设置位图文件头
	DWORD dwDIBSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwPaletteSize + dwBmBitsSize;  
	bmfHdr.bfSize = dwDIBSize;
	bmfHdr.bfReserved1 = 0;
	bmfHdr.bfReserved2 = 0;
	bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER) + dwPaletteSize;
	
	HANDLE hFile = CreateFile(/*m_strFilePath*/this->m_str_save_path, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);//创建位图文件   
	DWORD dwWritten;
	WriteFile(hFile, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);	// 写入位图文件头
	WriteFile(hFile, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);// 写入位图文件其余内容
	
	GlobalUnlock(hDib);   //清除   
	GlobalFree(hDib);
	CloseHandle(hFile); 	
	
}

void CDlgPrintScreen::CopyBmpToClipBoard(HBITMAP hBitmap)
{
	OpenClipboard() ; 	//打开剪贴板，并将位图拷到剪贴板上 
	EmptyClipboard(); 
	SetClipboardData(CF_BITMAP, hBitmap);
	CloseClipboard(); 	//关闭剪贴板  
}

 转载自  codeproject

另外 这个也很好 http://www.cnblogs.com/xiangism/archive/2012/06/21/2557901.html