1 using System;
  2 using System.Collections.Generic;
  3 using System.ComponentModel;
  4 using System.Data;
  5 using System.Drawing;
  6 using System.Text;
  7 using System.Windows.Forms;
  8 using System.Data.OleDb;
  9 using System.Xml;
 10 namespace Test
 11 {
 12     public partial class Form1 : Form
 13     {
 14         private bool MouseIsDown = false;
 15         private int _x, _y;
 16         private Rectangle MouseRect = Rectangle.Empty;
 17         public Form1()
 18         {
 19             InitializeComponent();
 20         }
 21         private void ResizeToRectangle(Point p)
 22         {
 23             DrawRectangle();
 24             MouseRect.Width = p.X - MouseRect.Left;
 25             MouseRect.Height = p.Y - MouseRect.Top;
 26             DrawRectangle();
 27         }
 28         private void DrawRectangle()
 29         {
 30             Rectangle rect = this.RectangleToScreen(MouseRect);
 31             ControlPaint.DrawReversibleFrame(rect, Color.White, FrameStyle.Dashed);
 32 
 33         }
 34         private void DrawStart(Point StartPoint)
 35         {
 36             barkPictureBox.Capture = true;
 37             Cursor.Clip = this.RectangleToScreen(new Rectangle(0, 0, ClientSize.Width, ClientSize.Height));
 38             MouseRect = new Rectangle(StartPoint.X, StartPoint.Y, 0, 0);
 39         }
 40 
 41 
 42         private void button1_Click(object sender, EventArgs e)
 43         {
 44 
 45         }
 46 
 47 
 48         void barkPictureBox_MouseUp(object sender, MouseEventArgs e)
 49         {
 50             barkPictureBox.Capture = false;
 51             Cursor.Clip = Rectangle.Empty;
 52             MouseIsDown = false;
 53             DrawRectangle();
 54 
 55             if (MouseRect.X == 0 || MouseRect.Y == 0 || MouseRect.Width == 0 || MouseRect.Height == 0)  //如果区域有一个是0就返回
 56             {
 57             }
 58             else
 59             {
 60                 ///代码
 61             }
 62 
 63             MouseRect = Rectangle.Empty;
 64             int sx = _x < e.X ? _x : e.X;
 65             int sy = _y < e.Y ? _y : e.Y;
 66             int w = Math.Abs(_x - e.X);
 67             int h = Math.Abs(_y - e.Y);
 68             Graphics g = Graphics.FromHwnd(pictureBox2.Handle);
 69             g.Clear(pictureBox2.BackColor);
 70             g.DrawImage(barkPictureBox.Image, new Rectangle(0, 0, w, h), sx, sy, w, h, GraphicsUnit.Pixel); 
 71         }
 72 
 73         void barkPictureBox_MouseMove(object sender, MouseEventArgs e)
 74         {
 75             if (MouseIsDown) ResizeToRectangle(new Point(e.X + barkPictureBox.Location.X, e.Y + barkPictureBox.Location.Y));
 76            
 77         }
 78 
 79         void barkPictureBox_MouseDown(object sender, MouseEventArgs e)
 80         {
 81             _x = e.X;
 82             _y = e.Y;
 83 
 84             MouseIsDown = true;
 85             DrawStart(new Point(e.X + barkPictureBox.Location.X, e.Y + barkPictureBox.Location.Y));
 86         }
 87 
 88 
 89  
 90 
 91    
 92 
 93         private void Form1_Load(object sender, EventArgs e)
 94         {
 95             barkPictureBox.MouseDown += new MouseEventHandler(barkPictureBox_MouseDown);
 96             barkPictureBox.MouseMove += new MouseEventHandler(barkPictureBox_MouseMove);
 97             barkPictureBox.MouseUp += new MouseEventHandler(barkPictureBox_MouseUp);
 98 
 99         }
100     }
101 }