How to get the screenshot of the form

Question

Any method to output the screenshot of an active form?

Answer 1

here is:




       public const int SRCCOPY = 0x00CC0020; // BitBlt dwRop parameter

    [DllImport("gdi32.dll")]
    public static extern bool BitBlt(IntPtr hObject, int nXDest, int nYDest,
        int nWidth, int nHeight, IntPtr hObjectSource,
        int nXSrc, int nYSrc, int dwRop);

    [DllImport("gdi32.dll")]
    public static extern bool StretchBlt(
          IntPtr hdcDest,      // handle to destination DC
          int nXOriginDest, // x-coord of destination upper-left corner
          int nYOriginDest, // y-coord of destination upper-left corner
          int nWidthDest,   // width of destination rectangle
          int nHeightDest,  // height of destination rectangle
          IntPtr hdcSrc,       // handle to source DC
          int nXOriginSrc,  // x-coord of source upper-left corner
          int nYOriginSrc,  // y-coord of source upper-left corner
          int nWidthSrc,    // width of source rectangle
          int nHeightSrc,   // height of source rectangle
          int dwRop       // raster operation code
        );


    [DllImport("gdi32.dll")]
    public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC, int nWidth,
        int nHeight);
    [DllImport("gdi32.dll")]
    public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
    [DllImport("gdi32.dll")]
    public static extern bool DeleteDC(IntPtr hDC);
    [DllImport("gdi32.dll")]
    public static extern bool DeleteObject(IntPtr hObject);
    [DllImport("gdi32.dll")]
    public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);



    [StructLayout(LayoutKind.Sequential)]
    public struct RECT
    {
        public int left;
        public int top;
        public int right;
        public int bottom;
    }

    [DllImport("user32.dll")]
    public static extern IntPtr GetDesktopWindow();
    [DllImport("user32.dll")]
    public static extern IntPtr GetWindowDC(IntPtr hWnd);
    [DllImport("user32.dll")]
    public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDC);
    [DllImport("user32.dll")]
    public static extern IntPtr GetWindowRect(IntPtr hWnd, ref RECT rect);

    private void run_test()
    {

        Rectangle rc = new Rectangle();
        Image img = ScreenToImage(ref rc, false);
        img.Save(@"C:\Users\ssaamm\Desktop\Capt44ure.JPG", System.Drawing.Imaging.ImageFormat.Jpeg);
        img.Dispose();

    }


    private Image ScreenToImage(ref Rectangle rcDest, bool IsPapaer)
    {
        IntPtr handle = this.Handle;

        //this.Handle
        // get te hDC of the target window
        IntPtr hdcSrc = GetWindowDC(handle);
        // get the size
        RECT windowRect = new RECT();
        GetWindowRect(handle, ref windowRect);
        int nWidth = windowRect.right - windowRect.left;
        int nHeight = windowRect.bottom - windowRect.top;

        if (IsPapaer)
        {
            float fRate = (float)rcDest.Width / nWidth;
            //float fHeight = nHeight * fRate;
            //rcDest.Height = (int)(nHeight * fRate);
            //rcDest.Width = (int)(rcDest.Width);// * fRate);
            rcDest.X = 0;
            rcDest.Y = 0;
            rcDest.Height = (int)(nHeight * fRate);
            //rcDest.Width = (int)(nWidth * fRate);
        }
        else
        {
            rcDest.X = 0;
            rcDest.Y = 0;
            rcDest.Height = nHeight;
            rcDest.Width = nWidth;
        }

        // create a device context we can copy to
        IntPtr hdcDest = CreateCompatibleDC(hdcSrc);
        // create a bitmap we can copy it to,
        // using GetDeviceCaps to get the width/height
        IntPtr hBitmap = CreateCompatibleBitmap(hdcSrc, rcDest.Width, rcDest.Height);
        // select the bitmap object
        IntPtr hOld = SelectObject(hdcDest, hBitmap);
        // bitblt over
        StretchBlt(hdcDest, rcDest.X, rcDest.Y, rcDest.Width, rcDest.Height, hdcSrc, 0, 0, nWidth, nHeight, SRCCOPY);
        // restore selection
        SelectObject(hdcDest, hOld);
        // clean up 
        DeleteDC(hdcDest);
        ReleaseDC(handle, hdcSrc);

        // get a .NET image object for it
        Image img = Image.FromHbitmap(hBitmap);
        // free up the Bitmap object
        DeleteObject(hBitmap);
        return img;
    }