首先建一个Windows应用程序

将Form1的 FormBorderStyle属性设置为None

主要是在Form1窗体触发三个事件：Form4_MouseDown，Form4_MouseMove，Form4_MouseUp

代码如下：

public partial class Form1 : Form{        Point mouseOff;                          //鼠标移动位置变量        bool leftFlag;                               //标签是否为左键        public Form1()        {            InitializeComponent();        } }

　　

//用代码设置窗体的起始位置

private void Form_Load(object sender, System.EventArgs e) {      this.Left=(int)((Screen.PrimaryScreen.Bounds.Width-this.Width)/2);      this.Top=(int)((Screen.PrimaryScreen.Bounds.Height-this.Height)/2); } private void Form1_MouseDown(object sender, MouseEventArgs e){　　if (e.Button == MouseButtons.Left)   {　　　　mouseOff = new Point(-e.X, -e.Y); //得到变量的值　　　　leftFlag = true;                              //点击左键按下时标注为true;　　} }private void Form1_MouseMove(object sender, MouseEventArgs e){   if (leftFlag)   {      Point mouseSet = Control.MousePosition;       mouseSet.Offset(mouseOff.X, mouseOff.Y); //设置移动后的位置      Location = mouseSet;  }}private void Form1_MouseUp(object sender, MouseEventArgs e){   if (leftFlag)   {     leftFlag = false;//释放鼠标后标注为false;　}} }