Windows Form Tips: 无边框窗口实现用鼠标拖拽的功能

有时候，为了达到一些特定的UI效果，我们可能会将一个Windows Form设定为无边框的形式（FormBorderStyle设置为None），但这时，窗口也将失去正常的用鼠标拖拽的行为。但下面这个例子可以让无边框窗口的鼠标拖拽功能又恢复回来。注意这个例子只支持按住鼠标左键拖拽。

假设窗口为Form1，我们为Form1增加MouseDown的响应函数Form1_MouseDown，以及MouseMove的响应函数Form1_MouseMove。

代码如下：

namespace Demo1{    using System.Drawing;    using System.Windows.Forms;    public partial class Form1 : Form    {        private Point startPoint;        public Form1()        {            this.InitializeComponent();        }        /// <summary>        /// Handles the MouseDown event of the Form1 control.        /// </summary>        /// <param name="sender">The source of the event.</param>        /// <param name="e">The <see cref="MouseEventArgs"/> instance containing the event data.</param>        private void Form1_MouseDown(object sender, MouseEventArgs e)        {            startPoint = new Point(                -e.X + SystemInformation.FrameBorderSize.Width,                 -e.Y - SystemInformation.FrameBorderSize.Height);        }        /// <summary>        /// Handles the MouseMove event of the Form1 control.        /// </summary>        /// <param name="sender">The source of the event.</param>        /// <param name="e">The <see cref="MouseEventArgs"/> instance containing the event data.</param>        private void Form1_MouseMove(object sender, MouseEventArgs e)        {            if (e.Button == MouseButtons.Left)            {                Point mousePosition = Control.MousePosition;                mousePosition.Offset(this.startPoint.X, this.startPoint.Y);                this.Location = mousePosition;            }        }    }}

然后你可以试试，这个无边框窗口是可以按住鼠标左键拖拽的。