做一个大小合适的图片，存成gif，这样背景透明。
把button的背景设为该图片，borderwidth为0，样式为flat，就可以了。
至于拖动，一般用类，没有一个一个按钮的编写拖动代码。下面是一个拖动类。
C#控件拖动和缩放类
这几天，因为项目需要，要对窗体上的控件进行拖动并对大小进行缩放，于是封装了该类：
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace ItpClientProtype
{
class DragResizeControl
{
#region Field
private const int Band = 5;
private const int MinWidth = 10;
private const int MinHeight = 10;
private static EnumMousePointPosition m_MousePointPosition;
private static Point p, p1;
#endregion
#region Inner Object
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
}
#endregion
#region Constructor
public DragResizeControl()
{
// Nothing to do.
}
#endregion
#region Public Method
public static void RegisterControl(Control control)
{
if (control != null)
{
control.MouseDown += new MouseEventHandler(control_MouseDown);
control.MouseLeave += new EventHandler(control_MouseLeave);
control.MouseMove += new MouseEventHandler(control_MouseMove);
}
}
public static void UnRegisterControl(Control control)
{
if (control != null)
{
control.MouseDown -= new MouseEventHandler(control_MouseDown);
control.MouseLeave -= new EventHandler(control_MouseLeave);
control.MouseMove -= new MouseEventHandler(control_MouseMove);
}
}
#endregion
private static void control_MouseDown(object sender, MouseEventArgs e)
{
p.X = e.X;
p.Y = e.Y;
p1.X = e.X;
p1.Y = e.Y;
}
private static void control_MouseLeave(object sender, EventArgs e)
{
m_MousePointPosition = EnumMousePointPosition.MouseSizeNone;
Control control = sender as Control;
control.Cursor = Cursors.Arrow;
}
private static void control_MouseMove(object sender, 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
Control control = sender as Control;
switch (m_MousePointPosition) //'改变光标
{
case EnumMousePointPosition.MouseSizeNone:
control.Cursor = Cursors.Arrow;
//'箭头
break;
case EnumMousePointPosition.MouseDrag:
control.Cursor = Cursors.SizeAll; //'四方向
break;
case EnumMousePointPosition.MouseSizeBottom:
control.Cursor = Cursors.SizeNS; //'南北
break;
case EnumMousePointPosition.MouseSizeTop:
control.Cursor = Cursors.SizeNS; //'南北
break;
case EnumMousePointPosition.MouseSizeLeft:
control.Cursor = Cursors.SizeWE; //'东西
break;
case EnumMousePointPosition.MouseSizeRight:
control.Cursor = Cursors.SizeWE; //'东西
break;
case EnumMousePointPosition.MouseSizeBottomLeft:
control.Cursor = Cursors.SizeNESW; //'东北到南西
break;
case EnumMousePointPosition.MouseSizeBottomRight:
control.Cursor = Cursors.SizeNWSE; //'东南到西北
break;
case EnumMousePointPosition.MouseSizeTopLeft:
control.Cursor = Cursors.SizeNWSE; //'东南到西北
break;
case EnumMousePointPosition.MouseSizeTopRight:
control.Cursor = Cursors.SizeNESW; //'东北到南西
break;
default:
break;
}
}
}
private static 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;
}
}
}
}
具体的调用方式如：
DragResizeControl.BindControl(this.button1);
就像普通的Windows Forms应用中注册控件的事件代码一样，只要绑定了控件后，就可以很方便地实现对控件的拖动与缩放了。
