本文实例讲述了C# WinForm实现窗体上控件自由拖动功能。分享给大家供大家参考，具体如下：
说明：首先在窗体上放一个PictrueBox控件，命名为pb1,拖动完整代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WinFormDrag
{
public partial class Form1 : Form
{
//鼠标按下坐标（control控件的相对坐标）
Point mouseDownPoint = Point.Empty;
//显示拖动效果的矩形
Rectangle rect = Rectangle.Empty;
//是否正在拖拽
bool isDrag = false ;
public Form1()
{
InitializeComponent();
}
private void Form1_Paint( object sender, PaintEventArgs e)
{
if (rect != Rectangle.Empty)
{
if (isDrag)
{ //画一个和Control一样大小的黑框
e.Graphics.DrawRectangle(Pens.Black, rect);
}
else
{
e.Graphics.DrawRectangle( new Pen( this .BackColor), rect);
}
}
}
/// <summary>
/// 按下鼠标时
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void pb1_MouseDown( object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
mouseDownPoint = e.Location;
//记录控件的大小
rect = pb1.Bounds;
}
}
/// <summary>
/// 移过时
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void pb1_MouseMove( object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
isDrag = true ;
//重新设置rect的位置，跟随鼠标移动
rect.Location = getPointToForm( new Point(e.Location.X - mouseDownPoint.X, e.Location.Y - mouseDownPoint.Y));
this .Refresh();
}
}
/// <summary>
/// 释放鼠标按钮时
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void pb1_MouseUp( object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
if (isDrag)
{
isDrag = false ;
//移动control到放开鼠标的地方
pb1.Location = rect.Location;
this .Refresh();
}
reset();
}
}
//重置变量
private void reset()
{
mouseDownPoint = Point.Empty;
rect = Rectangle.Empty;
isDrag = false ;
}
//把相对与control控件的坐标，转换成相对于窗体的坐标。
private Point getPointToForm(Point p)
{
return this .PointToClient(pb1.PointToScreen(p));
}
}
}
希望本文所述对大家C#程序设计有所帮助。
dy("nrwz");
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