using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace Client {     public partial class Catch : Form     {         public Catch()         {             InitializeComponent();         }         用户变量#region 用户变量         private Point DownPoint = Point.Empty;//记录鼠标按下坐标，用来确定绘图起点         private bool CatchFinished = false;//用来表示是否截图完成         private bool CatchStart = false;//表示截图开始         private Bitmap originBmp;//用来保存原始图像         private Rectangle CatchRect;//用来保存截图的矩形         #endregion         //窗体初始化操作         private void Catch_Load(object sender, EventArgs e)         {             this.SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint, true);             this.UpdateStyles();             //以上两句是为了设置控件样式为双缓冲，这可以有效减少图片闪烁的问题，关于这个大家可以自己去搜索下             originBmp = new Bitmap(this.BackgroundImage);//BackgroundImage为全屏图片，我们另用变量来保存全屏图片         }         //鼠标右键点击结束截图         private void Catch_MouseClick(object sender, MouseEventArgs e)         {             if (e.Button == MouseButtons.Right)             {                 this.DialogResult = DialogResult.OK;                 this.Close();             }         }         //鼠标左键按下时动作         private void Catch_MouseDown(object sender, MouseEventArgs e)         {             if (e.Button == MouseButtons.Left)             {                 if (!CatchStart)                 {//如果捕捉没有开始                     CatchStart = true;                     DownPoint = new Point(e.X, e.Y);//保存鼠标按下坐标                 }             }         }         private void Catch_MouseMove(object sender, MouseEventArgs e)         {             if (CatchStart)             {//如果捕捉开始                 Bitmap destBmp = (Bitmap)originBmp.Clone();//新建一个图片对象，并让它与原始图片相同                 Point newPoint = new Point(DownPoint.X, DownPoint.Y);//获取鼠标的坐标                 Graphics g = Graphics.FromImage(destBmp);//在刚才新建的图片上新建一个画板                 Pen p = new Pen(Color.Blue,1);                 int width = Math.Abs(e.X - DownPoint.X), height = Math.Abs(e.Y - DownPoint.Y);//获取矩形的长和宽                 if (e.X < DownPoint.X)                 {                     newPoint.X = e.X;                 }                 if (e.Y < DownPoint.Y)                 {                     newPoint.Y = e.Y;                 }                 CatchRect = new Rectangle(newPoint,new Size(width,height));//保存矩形                 g.DrawRectangle(p,CatchRect);//将矩形画在这个画板上                 g.Dispose();//释放目前的这个画板                 p.Dispose();                 Graphics g1 = this.CreateGraphics();//重新新建一个Graphics类                 //如果之前那个画板不释放，而直接g=this.CreateGraphics()这样的话无法释放掉第一次创建的g,因为只是把地址转到新的g了．如同string一样                 g1 = this.CreateGraphics();//在整个全屏窗体上新建画板                 g1.DrawImage(destBmp,new Point(0,0));//将刚才所画的图片画到这个窗体上                 //这个也可以属于二次缓冲技术，如果直接将矩形画在窗体上，会造成图片抖动并且会有无数个矩形．                 g1.Dispose();                 destBmp.Dispose();//要及时释放，不然内存将会被大量消耗             }         }         private void Catch_MouseUp(object sender, MouseEventArgs e)         {             if (e.Button == MouseButtons.Left)             {                 if (CatchStart)                 {                     CatchStart = false;                     CatchFinished = true;                 }             }         }         //鼠标双击事件，如果鼠标位于矩形内，则将矩形内的图片保存到剪贴板中         private void Catch_MouseDoubleClick(object sender, MouseEventArgs e)         {             if (e.Button == MouseButtons.Left&&CatchFinished)             {                 if (CatchRect.Contains(new Point(e.X, e.Y)))                 {                     Bitmap CatchedBmp = new Bitmap(CatchRect.Width, CatchRect.Height);//新建一个于矩形等大的空白图片                     Graphics g = Graphics.FromImage(CatchedBmp);                     g.DrawImage(originBmp, new Rectangle(0, 0, CatchRect.Width, CatchRect.Height), CatchRect, GraphicsUnit.Pixel);                     //把orginBmp中的指定部分按照指定大小画在画板上                     Clipboard.SetImage(CatchedBmp);//将图片保存到剪贴板                     g.Dispose();                     CatchFinished = false;                     this.BackgroundImage = originBmp;                     CatchedBmp.Dispose();                     this.DialogResult = DialogResult.OK;                     this.Close();                 }             }         }     } }

 private void bCatch_Click(object sender, EventArgs e)         {             if (bCatch_HideCurrent.Checked)             {                 this.Hide();//隐藏当前窗体                 Thread.Sleep(50);//让线程睡眠一段时间，窗体消失需要一点时间                 Catch CatchForm = new Catch();                 Bitmap CatchBmp = new Bitmap(Screen.AllScreens[0].Bounds.Width, Screen.AllScreens[0].Bounds.Height);//新建一个和屏幕大小相同的图片                         Graphics g = Graphics.FromImage(CatchBmp);                 g.CopyFromScreen(new Point(0, 0), new Point(0, 0), new Size(Screen.AllScreens[0].Bounds.Width, Screen.AllScreens[0].Bounds.Height));//保存全屏图片                 CatchForm.BackgroundImage = CatchBmp;//将Catch窗体的背景设为全屏时的图片                 if (CatchForm.ShowDialog() == DialogResult.OK)                 {//如果Catch窗体结束,就将剪贴板中的图片放到信息发送框中                     IDataObject iData = Clipboard.GetDataObject();                     DataFormats.Format myFormat = DataFormats.GetFormat(DataFormats.Bitmap);                     if (iData.GetDataPresent(DataFormats.Bitmap))                     {                         richtextbox1.Paste(myFormat);                         Clipboard.Clear();//清除剪贴板中的对象                     }                     this.Show();//重新显示窗体                 }             }         }