在C#中，如何实现可拖动控件

Question

private Point mouse_offset;private void Control_MouseDown(object sender,System.Windows.Forms.MouseEventArgs e)
{
      mouse_offset = new Point(-e.X,-e.Y);
}private void Control_MouseMove(object sender,System.Windows.Forms.MouseEventArgs e)
{
   if (e.Button == MouseButtons.Left)
   {
      Point mousePos = Control.MousePosition;
      mousePos.Offset(mouse_offset.X, mouse_offset.Y);
      ((Control)sender).Location = ((Control)sender).Parent.PointToClient(mousePos);
   }
}

Answer 1

To Tigatron(Illidian):
 该代码可实现控件移动，但是却不能画控件的移动柄。

Answer 2

经过不断实践，本人发现一种实现方法,与大家共享，如果有何建议，请勿吝啬，跟贴或发Email给我都可，Email:[email protected]：

Answer 3

tracker.csusing System;
using System.Drawing;
using System.Windows.Forms;namespace Second
{
/// <summary>
/// Tracker &micro;&Auml;&Otilde;&ordf;&Ograve;&ordf;&Euml;&micro;&Atilde;÷&iexcl;&pound;
/// </summary>
public class Tracker
{
public enum Hits {Nothing = 0, LeftTop, Top, RightTop, Right, RightBottom, Bottom, LeftBottom, Left, Middle};
public enum MouseEvent {Down, Up, Move};
public Tracker()
{
//
// TODO: &Ocirc;&Uacute;&acute;&Euml;&acute;&brvbar;&Igrave;í&frac14;&Oacute;&sup1;&sup1;&Ocirc;ì&ordm;&macr;&Ecirc;&yacute;&Acirc;&szlig;&frac14;&shy;
TrackRect = new Rectangle(rect.Left, rect.Top, rect.Width, rect.Height);
//
} /// <summary>
/// Get all rects of eight grab-handlers
/// </summary>
/// <returns>array of rects</returns>
private Rectangle[] GetHandleRects()
{

Rectangle[] rects = new Rectangle[HandlerCount]; rects[0] = new Rectangle(rect.Left - HandleSize, rect.Top - HandleSize, HandleSize, HandleSize);  //LeftTop
rects[1] = new Rectangle((rect.Left + rect.Right - HandleSize) / 2, rect.Top - HandleSize, HandleSize, HandleSize); //Top
rects[2] = new Rectangle(rect.Right, rect.Top - HandleSize, HandleSize, HandleSize); //RightTop
rects[3] = new Rectangle(rect.Right, (rect.Top + rect.Bottom - HandleSize) / 2, HandleSize, HandleSize); //Right
rects[4] = new Rectangle(rect.Right, rect.Bottom, HandleSize, HandleSize); //RightBottom
rects[5] = new Rectangle((rect.Left + rect.Right - HandleSize) / 2, rect.Bottom, HandleSize, HandleSize); //Bottom
rects[6] = new Rectangle(rect.Left - HandleSize, rect.Bottom, HandleSize, HandleSize); //LeftBottom
rects[7] = new Rectangle(rect.Left - HandleSize, (rect.Top + rect.Bottom - HandleSize) / 2, HandleSize, HandleSize); //Left return rects;
} /// <summary>
/// Draw tracker
/// </summary>
/// <param name="g">Graphics</param>
public virtual void Draw(Graphics g)
{
Rectangle area = new Rectangle(rect.Left - HandleSize, rect.Top - HandleSize, rect.Width + 2 * HandleSize, rect.Height + 2 * HandleSize);
ControlPaint.DrawBorder(g, area, Color.Blue, ButtonBorderStyle.Dotted);
ControlPaint.DrawBorder(g, rect, Color.Blue, ButtonBorderStyle.Dotted);
//ControlPaint.DrawButton(g, rect, ButtonState.Normal); Rectangle[] rects = GetHandleRects();
foreach(Rectangle rectangle in rects)
{
ControlPaint.DrawGrabHandle(g, rectangle, true, true);
} if(!TrackRect.Equals(rect))
{
ControlPaint.DrawBorder(g, TrackRect, Color.Blue, ButtonBorderStyle.Dotted);
}
} /// <summary>
/// Get handle  been hitted
/// </summary>
/// <param name="point">the point hitted</param>
/// <returns>the handle  been hitted</returns>
public Hits HitTest(Point point)
{
if( rect.Contains(point) )
return Hits.Middle;
Rectangle[] rects = GetHandleRects();
for(Hits i = Hits.LeftTop; (int)i <= rects.Length; i++)
{
if( rects[(int)i - 1].Contains(point))
return i;
} return Hits.Nothing;
} /// <summary>
/// set the current cursor depend on handle been hitted
/// </summary>
/// <param name="form">the form track on</param>
/// <param name="hit">the handle been hitted</param>
public void SetCursor(Form form, Hits hit)
{
switch(hit)
{
case Hits.LeftTop:
case Hits.RightBottom:
form.Cursor = Cursors.SizeNWSE;
break;
case Hits.Top:
case Hits.Bottom:
form.Cursor = Cursors.SizeNS;
break;
case Hits.RightTop:
case Hits.LeftBottom:
form.Cursor = Cursors.SizeNESW;
break;
case Hits.Left:
case Hits.Right:
form.Cursor = Cursors.SizeWE;
break;
case Hits.Middle:
form.Cursor = Cursors.SizeAll;
break;
default:
form.Cursor = Cursors.Arrow;
break;
} }