C# WinForm控件的拖动和缩放的实现

原文：http://www.codesky.net/article/200908/127342.html

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。