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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