一个拖动无标题栏窗体的方法

 Invoicing_Tube
{
    public partial class login : Form
    {
        public login()
        {
            InitializeComponent();
        }
        //定义一下坐标
        private Point mouseOffset;
        //判断一下是否按下了左键默认的为False
        private bool isMouseDown = false;
        private void login_MouseDown(object sender, MouseEventArgs e)
        {
            try
            {
                //X轴
                int xOffset;
                //Y轴
                int yOffset;
                //当按下左键时
                if (e.Button == MouseButtons.Left)
                {
                     //X轴为当前的位置加上窗体的长度
                    xOffset = -e.X - SystemInformation.FrameBorderSize.Width;
                    //Y轴为当前的位置加上窗体的高度
                    yOffset = -e.Y - SystemInformation.CaptionHeight -
                        SystemInformation.FrameBorderSize.Height;
                    //综合一下坐标
                    mouseOffset = new Point(xOffset, yOffset);
                    //表示按下了左键
                    isMouseDown = true;
                }
            }
            catch (Exception ee)
            {
                MessageBox.Show(ee.Message.ToString(), "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
        }

        private void login_MouseMove(object sender, MouseEventArgs e)
        {
            try
            {
                //如果按下了左键
                if (isMouseDown)
                {
                    //前当的坐标==鼠标的位置
                    Point mousePos = Control.MousePosition;
                    mousePos.Offset(mouseOffset.X, mouseOffset.Y);
                    Location = mousePos;
                }
            }
            catch (Exception ee)
            {
                MessageBox.Show(ee.Message.ToString(), "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
        }

        private void login_MouseUp(object sender, MouseEventArgs e)
        {
            try
            {
                if (e.Button == MouseButtons.Left)
                {
                    isMouseDown = false;
                }
            }
            catch (Exception ee)
            {
                MessageBox.Show(ee.Message.ToString(), "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
        }
    }
}

下载全部代码：http://www.cckan.net/forum.php?mod=viewthread&tid=68