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。 

来源：http://blog.csdn.net/u012252959/article/details/50563304