C# 如何用鼠标拖出虚线框，释放鼠标虚框消失，就和在windows桌面上拖动鼠标一样

fuji2007 2007-12-20 05:23:25

rt，谢谢！

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wttmmllgg 2012-02-21

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学习了！不过还想问下怎么做出提示框的效果？比如当鼠标移到一张图片上的时候会出来一个矩形信息框，鼠标移走之后又没了？

etindex 2008-06-17

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我试了一下，可是我拉出的虚线框并没有消失，应该是OnMouseUp事件出问题了，可是就是解决不了，郁闷:-(

jacksu19 2008-06-05

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标记一书签。
然后学习...

null1 2007-12-22

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Cursor.Clip = this.RectangleToScreen(this.Bounds);
的作用是限制鼠标不要超出绘图窗口，RectangleToScreen是转换到屏幕坐标系。这里的this与实际的绘图部分不一致时就有问题了，因此需要根据情况选择。

hiddkiller 2007-12-21

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呵呵

zhuds 2007-12-21

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学习了,好！！！

funlove999 2007-12-21

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学习了

fuji2007 2007-12-21

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ok，搞定，太感谢了

「已注销」 2007-12-20

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mark

hiddkiller 2007-12-20

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命名空间 

using System.Drawing; 



定义两个变量 

bool MouseIsDown=false; 

Rectangle MouseRect   =   Rectangle.Empty; 



定义三个方法 

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); 

   ControlPaint.DrawReversibleFrame(rect,Color.White,FrameStyle.Dashed); 

} 



private void DrawStart(Point StartPoint) 

{ 

   this.Capture = true; 

   Cursor.Clip = this.RectangleToScreen(this.Bounds); 

   MouseRect = new Rectangle(StartPoint.X,StartPoint.Y,0,0); 

} 



在鼠标按下事件里写（一定是鼠标按下事件MouseDown   因为我的参数e是鼠标数据对象 

（不过你也可以传坐标）） 

MouseIsDown = true; 

DrawStart(e.Location); 



在鼠标移动（MouseMove）事件里写     

if(MouseIsDown) 

    ResizeToRectangle(e.Location); 





在鼠标释放（MouseUp）事件里写       

this.Capture = false; 

Cursor.Clip = Rectangle.Empty; 

MouseIsDown = false; 

DrawRectangle(); 

MouseRect = Rectangle.Empty;

hiddkiller 2007-12-20

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using   System; 

using   System.Collections.Generic; 

using   System.ComponentModel; 

using   System.Data; 

using   System.Drawing; 

using   System.Text; 

using   System.Windows.Forms; 



namespace   Probation 

{ 

        public   partial   class   frmMain   :   Form 

        { 

                bool   MouseIsDown   =   false; 

                Rectangle   MouseRect   =   Rectangle.Empty;   

                public   frmMain() 

                { 

                        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(); 

                        MouseRect   =   Rectangle.Empty; 

                } 

                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);   

                      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);   

                }   

        } 

}