鼠标拖动区域边框，选中边框内的控件

 

   网上实现该功能的代码很少，为了大家都学习就把它发出来
   public partial class Form11 : Form      
     { 

        bool MouseIsDown = false;    
         Rectangle MouseRect = Rectangle.Empty;   

          Rectangle RgionRect = Rectangle.Empty;  
         public Form11()    
         {    
             InitializeComponent();    
             this.MouseDown += new MouseEventHandler(frmMain_MouseDown);    
             this.MouseMove += new MouseEventHandler(frmMain_MouseMove);    
             this.MouseUp += new MouseEventHandler(frmMain_MouseUp);     
         }    
         void frmMain_MouseUp(object sender, MouseEventArgs e)    
         {    
             this.Capture = false;    
             Cursor.Clip = Rectangle.Empty;    
             MouseIsDown = false;    
             DrawRectangle();    

            //画完后的矩形区域保存到RgionRect 矩形内，然后在RgionRect 矩形内判断控件是否在该矩形内，设置选中状态

            RgionRect =MouseRect ;
           //判断选中状态
            CheckSelect(panel1);
             MouseRect = Rectangle.Empty;    
         }    

   void CheckSelect(Panel gb)
            {
                foreach (Label item in gb.Controls)
                {
                       //得到控件的矩形区域
                        Rectangle controlSize = new Rectangle(item.Location, item.Size);
                      //得到画出的矩形位置。位置不一定在左上角要转换后在判断
                        Point rangPoint = SaveRect.Location;
                        if (SaveRect.Width < 0 && SaveRect.Height > 0)
                        {
                            SaveRect.Location = new Point(rangPoint.X - Math.Abs(SaveRect.Width), rangPoint.Y);
                            SaveRect.Width = Math.Abs(SaveRect.Width);
                        }
                        else if (SaveRect.Width >= 0 && SaveRect.Height < 0)
                        {
                            SaveRect.Location = new Point(rangPoint.X, rangPoint.Y - Math.Abs(SaveRect.Height));
                            SaveRect.Height = Math.Abs(SaveRect.Height);
                        }
                        else if (SaveRect.Width < 0 && SaveRect.Height < 0)
                        {
                            SaveRect.Location = new Point(rangPoint.X - Math.Abs(SaveRect.Width), rangPoint.Y - Math.Abs(SaveRect.Height));
                            SaveRect.Height = Math.Abs(SaveRect.Height);
                            SaveRect.Width = Math.Abs(SaveRect.Width);
                        }
                       //如果画出的矩形和控件的矩形相交叉
                        if (SaveRect.IntersectsWith(controlSize))
                        {
                            item.Text = "选中";           
                        }     
                }
            }
         void frmMain_MouseMove(object sender, MouseEventArgs e)    
         {    
             if (MouseIsDown)    
                 ResizeToRectangle(e.Location);    
         }    
         void frmMain_MouseDown(object sender, MouseEventArgs e)    
         {    
             MouseIsDown = true;    
             DrawStart(e.Location);    
         }    
         private void ResizeToRectangle(Point p)    
         {    
             DrawRectangle();    
             MouseRect.Width = p.X - MouseRect.Left;    
             MouseRect.Height = p.Y - MouseRect.Top;    
             DrawRectangle();    
         }    
         private void DrawRectangle()    
         {    
             Rectangle rect = this.RectangleToScreen(MouseRect);    

            //这里画的矩形是相反的，起始点可能在右上，可能在左下
             ControlPaint.DrawReversibleFrame(rect, Color.White, FrameStyle.Dashed);    
         }    
         private void DrawStart(Point StartPoint)    
         {    
             this.Capture = true;    
             Cursor.Clip = this.RectangleToScreen(new Rectangle(0, 0, ClientSize.Width, ClientSize.Height));    
             MouseRect = new Rectangle(StartPoint.X, StartPoint.Y, 0, 0);    
         }     
     }