C#中WinForm控件的拖动和缩放的实现代码

c# winform控件的拖动和缩放是个很有用的功能。实现起来其实很简单的，主要是设计控件的mousedown、mouseleave、mousemove事件,下面的几个步骤将逐步实现c# winform控件的拖动和缩放的功能。

1、定义一个枚举类型，描述光标状态  

private enum enummousepointposition  
  {  
  mousesizenone  = 0, //'无  
  mousesizeright  = 1, //'拉伸右边框  
  mousesizeleft  = 2, //'拉伸左边框  
  mousesizebottom  = 3, //'拉伸下边框  
  mousesizetop  = 4, //'拉伸上边框  
  mousesizetopleft = 5, //'拉伸左上角  
  mousesizetopright = 6, //'拉伸右上角  
  mousesizebottomleft = 7, //'拉伸左下角  
  mousesizebottomright= 8, //'拉伸右下角  
  mousedrag  = 9  // '鼠标拖动  
  }  

2、定义几个变量  

 const int band = 5;  
  const int minwidth=10;  
  const int minheight=10;  
  private enummousepointposition m_mousepointposition;  
  private point p,p1;  

3、定义自己的mymousedown事件   

private void mymousedown(object sender,system.windows.forms.mouseeventargs e)  
{  
 p.x=e.x;  
 p.y=e.y;  
 p1.x=e.x;  
 p1.y=e.y;    
}  

4、定义自己的mymouseleave事件  

 private void mymouseleave(object sender, system.eventargs e)  
{  
 m_mousepointposition = enummousepointposition.mousesizenone;  
 this.cursor=cursors.arrow;  
}  

5、设计一个函数，确定光标在控件不同位置的样式   

private enummousepointposition mousepointposition(size size,system.windows.forms.mouseeventargs e)  
{  
  
 if ((e.x >= -1 * band) | (e.x <= size.width) | (e.y >= -1 * band) | (e.y <= size.height))   
 {  
 if (e.x < band)   
 {  
  if (e.y < band) {return enummousepointposition.mousesizetopleft;}  
  else   
  {  
  if (e.y > -1 * band + size.height)   
  {return enummousepointposition.mousesizebottomleft;}  
  else   
  {return enummousepointposition.mousesizeleft;}  
  }  
 }  
 else  
 {  
  if (e.x > -1 * band + size.width)  
  {  
  if (e.y < band)  
  {return enummousepointposition.mousesizetopright;}  
  else   
  {  
   if (e.y > -1 * band + size.height)  
   {return enummousepointposition.mousesizebottomright;}  
   else  
   {return enummousepointposition.mousesizeright;}  
  }  
  }  
  else  
  {  
  if (e.y < band)   
  {return enummousepointposition.mousesizetop;}  
  else  
  {  
   if (e.y > -1 * band + size.height)   
   {return enummousepointposition.mousesizebottom;}  
   else   
   {return enummousepointposition.mousedrag;}  
  }  
  }  
 }  
 }  
 else   
 {return enummousepointposition.mousesizenone;}  
}  

6、定义自己的mymousemove事件，在这个事件里，会使用上面设计的函数    

  private void mymousemove(object sender,system.windows.forms.mouseeventargs e)  
  {  
  control lctrl =(sender as control);  
  
  if (e.button==mousebuttons.left)  
  {  
   switch (m_mousepointposition)  
   {  
   case enummousepointposition.mousedrag:     
    lctrl.left =lctrl.left+ e.x - p.x;  
    lctrl.top =lctrl.top+ e.y - p.y;  
    break;  
   case enummousepointposition.mousesizebottom:  
    lctrl.height = lctrl.height + e.y - p1.y;  
    p1.x=e.x;  
    p1.y=e.y; //'记录光标拖动的当前点  
    break;  
   case enummousepointposition.mousesizebottomright:  
    lctrl.width  = lctrl.width + e.x - p1.x;  
    lctrl.height = lctrl.height + e.y - p1.y;  
    p1.x=e.x;  
    p1.y=e.y; //'记录光标拖动的当前点  
    break;  
   case enummousepointposition.mousesizeright:  
    lctrl.width  = lctrl.width + e.x - p1.x;     
//    lctrl.height = lctrl.height + e.y - p1.y;  
    p1.x=e.x;  
    p1.y=e.y; //'记录光标拖动的当前点  
    break;  
   case enummousepointposition.mousesizetop:  
    lctrl.top  = lctrl.top + (e.y - p.y);  
    lctrl.height = lctrl.height - (e.y - p.y);  
    break;  
   case enummousepointposition.mousesizeleft:  
    lctrl.left  = lctrl.left + e.x - p.x;  
    lctrl.width  = lctrl.width - (e.x - p.x);  
    break;  
   case enummousepointposition.mousesizebottomleft:  
    lctrl.left  = lctrl.left + e.x - p.x;  
    lctrl.width  = lctrl.width - (e.x - p.x);  
    lctrl.height = lctrl.height+ e.y - p1.y;  
    p1.x=e.x;  
    p1.y=e.y; //'记录光标拖动的当前点  
    break;  
   case enummousepointposition.mousesizetopright:  
    lctrl.top  = lctrl.top + (e.y - p.y);  
    lctrl.width  = lctrl.width + (e.x - p1.x);  
    lctrl.height = lctrl.height - (e.y - p.y);  
    p1.x=e.x;  
    p1.y=e.y; //'记录光标拖动的当前点  
    break;  
   case enummousepointposition.mousesizetopleft:  
    lctrl.left  = lctrl.left + e.x - p.x;  
    lctrl.top  = lctrl.top + (e.y - p.y);  
    lctrl.width  = lctrl.width - (e.x - p.x);  
    lctrl.height = lctrl.height - (e.y - p.y);  
    break;  
   default:  
    break;  
   }  
   if (lctrl.width<minwidth) lctrl.width=minwidth;  
   if (lctrl.height<minheight) lctrl.height=minheight;     
  
  }  
  else  
  {  
   m_mousepointposition = mousepointposition(lctrl.size, e);  //'判断光标的位置状态  
   switch (m_mousepointposition)  //'改变光标  
   {  
   case enummousepointposition.mousesizenone:  
    this.cursor = cursors.arrow;    //'箭头  
    break;  
   case enummousepointposition.mousedrag:  
    this.cursor = cursors.sizeall;   //'四方向  
    break;  
   case enummousepointposition.mousesizebottom:  
    this.cursor = cursors.sizens;    //'南北  
    break;  
   case enummousepointposition.mousesizetop:  
    this.cursor = cursors.sizens;    //'南北  
    break;  
   case enummousepointposition.mousesizeleft:  
    this.cursor = cursors.sizewe;    //'东西  
    break;  
   case enummousepointposition.mousesizeright:  
    this.cursor = cursors.sizewe;    //'东西  
    break;  
   case enummousepointposition.mousesizebottomleft:  
    this.cursor = cursors.sizenesw;   //'东北到南西  
    break;  
   case enummousepointposition.mousesizebottomright:  
    this.cursor = cursors.sizenwse;   //'东南到西北  
    break;  
   case enummousepointposition.mousesizetopleft:  
    this.cursor = cursors.sizenwse;   //'东南到西北  
    break;  
   case enummousepointposition.mousesizetopright:  
    this.cursor = cursors.sizenesw;   //'东北到南西  
    break;  
   default:  
    break;  
   }  
  }  
  
  }  

7、制作一个初始化过程，将界面panel1上的所有控件都绑定mymousedown、mymouseleave、mymousemove事件，记得在form初始化或者form_load时先执行它。  

 private void initproperty()  
{  
 for(int i = 0; i < this.panel1.controls.count; i++)   
 {   
 this.panel1.controls[i].mousedown+= new system.windows.forms.mouseeventhandler(mymousedown);  
 this.panel1.controls[i].mouseleave+= new system.eventhandler(mymouseleave);  
 this.panel1.controls[i].mousemove += new system.windows.forms.mouseeventhandler(mymousemove);  
 }  
  
}  

8、ok，在运行之前你在panel1上放几个控件，执行程序，应该可以随便移动、改变其大小了 

c# winform控件的拖动和缩放的实现就此完成。 

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