找到一个截全屏代码，不过不会用，哪位高手救一下新人

找到一个截全屏代码，不过不会用，谁救一下新人？
  public static Bitmap CopyPrimaryScreen()
        {
            Screen s = Screen.PrimaryScreen;
            Rectangle r = s.Bounds;
            int w = r.Width;
            int h = r.Height;
            Bitmap bmp = new Bitmap(w, h);
            Graphics g = Graphics.FromImage(bmp);
            g.CopyFromScreen
            (
            new Point(0, 0),
            new Point(0, 0),
            new Size(w, h)
            );
            return bmp;
        }


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创个按键点击使用上面代码，保存到C盘A.BMP。不会搞，谁会教一下，谢谢啦
[解决办法]
参考：http://www.cnblogs.com/zhili/p/CaptureTool.html
[解决办法]

btnClick:
    Bitmap bitmap=CopyPrimaryScreen();
    bitmap.Save("C:\\A.bmp");
    bitmap.Dispose();

public static Bitmap CopyPrimaryScreen()
{
    Screen s = Screen.PrimaryScreen;
    Rectangle r = s.Bounds;
    int w = r.Width;
    int h = r.Height; 
 
    Bitmap bmp = new Bitmap(w, h,System.Drawing.Imaging.PixelFormat.Format32bppArgb);
    Graphics g = Graphics.FromImage(bmp);
    g.CopyFromScreen
    (
       new Point(0, 0),
       new Point(0, 0),
       new Size(w, h)
    );
    return bmp;
}

btnClick:
    Bitmap bitmap=CopyPrimaryScreen();
    bitmap.Save("C:\\A.bmp",System.Drawing.Imaging.ImageFormat.Png);
    bitmap.Dispose();