发布一个屏幕捕捉类

前做时间完成了一个LED点陈显示屏系统，
其中有个功能是需要动态捕捉屏幕上显示的内容发送到LED屏，
现成整理出了一个屏幕捕捉类。如下:

using System;
 using System.Collections.Generic;
 using System.Text;
 using System.Runtime.InteropServices;
 using System.Drawing.Imaging;
 using System.Drawing;namespace wuChang
 {
     /// <summary>
     /// 屏幕捕捉类
    /// 无常作品
     /// 
     /// </summary>
     internal class ScreenCapture : IDisposable
     {
         private static ScreenCapture instance = null;        internal static ScreenCapture Instance
         {
             get
             {
                 if (instance == null)
                 {
                     instance = new ScreenCapture();
                 }
                 return ScreenCapture.instance;
             }
         }
         int hdcSrc,
             hdcDest;
         private ScreenCapture()
         {
             hdcSrc = User32.GetWindowDC(User32.GetDesktopWindow());
             hdcDest = GDI32.CreateCompatibleDC(hdcSrc);
         }
         /// <summary>
         /// 屏幕捕捉
         /// </summary>
         /// <param name="rct">要捕捉的桌面区域</param>
         /// <returns>捕获后的图形</returns>
         internal Bitmap Capture(Rectangle rct)
         {
             int hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc, rct.Width, rct.Height);            GDI32.SelectObject(hdcDest, hBitmap);
             GDI32.BitBlt(hdcDest, 0, 0, rct.Width, rct.Height,
                             hdcSrc, rct.Left, , 0x00CC0020);
             Bitmap image = new Bitmap(Image.FromHbitmap(new IntPtr(hBitmap)),
                      Image.FromHbitmap(new IntPtr(hBitmap)).Width,
                      Image.FromHbitmap(new IntPtr(hBitmap)).Height);            GDI32.DeleteObject(hBitmap);
             return image;        }
        #region IDisposable Members
        public void Dispose()
         {
             User32.ReleaseDC(User32.GetDesktopWindow(), hdcSrc);
             GDI32.DeleteDC(hdcDest);
         }
         #endregion     }
     //下面二个类来自:http://www.c-sharpcorner.com/Code/2003/Dec/ScreenCapture.asp    class GDI32
     {
         [DllImport("GDI32.dll")]
         public static extern bool BitBlt(int hdcDest, int nXDest, int nYDest,
                                          int nWidth, int nHeight, int hdcSrc,
                                          int nXSrc, int nYSrc, int dwRop);
         [DllImport("GDI32.dll")]
         public static extern int CreateCompatibleBitmap(int hdc, int nWidth,
                                                          int nHeight);
         [DllImport("GDI32.dll")]
         public static extern int CreateCompatibleDC(int hdc);
         [DllImport("GDI32.dll")]
         public static extern bool DeleteDC(int hdc);
         [DllImport("GDI32.dll")]
         public static extern bool DeleteObject(int hObject);
         [DllImport("GDI32.dll")]
         public static extern int GetDeviceCaps(int hdc, int nIndex);
         [DllImport("GDI32.dll")]
         public static extern int SelectObject(int hdc, int hgdiobj);
     }    class User32
     {
         [DllImport("User32.dll")]
         public static extern int GetDesktopWindow();
         [DllImport("User32.dll")]
         public static extern int GetWindowDC(int hWnd);
         [DllImport("User32.dll")]
         public static extern int ReleaseDC(int hWnd, int hDC);
     } }

使用方法：
1、捕捉主显示器的全屏内容

wuChang.ScreenCapture.Instance.Capture(Screen.PrimaryScreen.Bounds).Save(@"c:\aa.bmp", ImageFormat.Bmp);2、捕捉当前窗口内容
 wuChang.ScreenCapture.Instance.Capture( this.Bounds ).Save(@"c:\aa.bmp", ImageFormat.Bmp);