/// <summary>    /// 继承自Form，但将FormBorderStyle设置为None    /// </summary>    public partial class TipForm : Form    {        public TipForm()        {            InitializeComponent();        }        /// <summary>        /// 鼠标按下位置，方便移动窗体        /// </summary>        private Point ptMouseDown;        /// <summary>        /// 窗体下部分尖头的坐标位置        /// </summary>        private Point position;        public Point Position        {            get { return position; }            set             {                 position = value;                SetPosition(position);            }        }        /// <summary>        /// 设置窗口的圆角半径        /// </summary>        private int radius = 50;        public int Radius        {            get { return radius; }            set { radius = value; }        }        /// <summary>        /// 重写OnPaint方法以绘制窗体边框        /// </summary>        /// <param name="e"></param>        protected override void OnPaint(PaintEventArgs e)        {            base.OnPaint(e);            Graphics graph = e.Graphics;            graph.SmoothingMode = SmoothingMode.AntiAlias;            GraphicsPath path = GetTipPath(ClientRectangle);            Rectangle rect = new Rectangle(ClientRectangle.X, ClientRectangle.Y,                ClientRectangle.Width, ClientRectangle.Height);            rect.Inflate(-1, -1);            GraphicsPath border = GetTipPath(rect);            GraphicsPath curve = new GraphicsPath();            graph.DrawPath(new Pen(Color.Black,2), border);            this.Region = new Region(path);        }        /// <summary>        /// 根据窗体下部的顶点位置设置窗体位置        /// </summary>        /// <param name="pos">屏幕坐标点</param>        public void SetPosition(Point pos)        {            this.Location = new Point(pos.X - Size.Width / 2,                pos.Y - Size.Height);        }        /// <summary>        /// 根据当前窗体的ClientRectangle属性获取Tip风格路径        /// </summary>        /// <param name="rect"></param>        /// <returns></returns>        private GraphicsPath GetTipPath(Rectangle rect)        {            GraphicsPath path = new GraphicsPath();            int height = rect.Height - Radius;            path.StartFigure();            path.AddArc(rect.X, rect.Y, Radius, Radius, 270, -90);            path.AddArc(rect.X, rect.Y + height - Radius, Radius, Radius,                 180, -90);            path.AddLine(                new Point(rect.X + Radius / 2, rect.Y + height),                new Point(rect.X + rect.Width / 2 - Radius / 2,                    rect.Y + height));            path.AddLine(               new Point(rect.X + rect.Width / 2 - Radius / 2,                   rect.Y + height),               new Point(rect.X + rect.Width / 2, rect.Y + height + Radius));            path.AddLine(               new Point(rect.X + rect.Width / 2, rect.Y + height + Radius),               new Point(rect.X + rect.Width / 2 + Radius / 2,                   rect.Y + height));            path.AddLine(                new Point(rect.X + rect.Width / 2 + Radius / 2,                    rect.Y + height),                new Point(rect.X + rect.Width - Radius / 2,                    rect.Y + height));            path.AddArc(rect.X + rect.Width - radius,                 rect.Y + height - Radius, Radius, Radius, 90, -90);            path.AddArc(rect.X + rect.Width - Radius, rect.Y,                 Radius, Radius, 0, -90);            path.AddLine(new Point(rect.X + rect.Width - Radius / 2, rect.Y),                 new Point(rect.X + Radius / 2, rect.Y));                        path.CloseFigure();            return path;        }        private void button1_Click(object sender, EventArgs e)        {            Close();        }        /// <summary>        /// 鼠标移动事件        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void TipForm_MouseMove(object sender, MouseEventArgs e)        {            if (e.Button == MouseButtons.Left)            {                Point pt = e.Location;                Location = new Point(Location.X + pt.X - ptMouseDown.X,                    Location.Y + pt.Y - ptMouseDown.Y);            }        }        /// <summary>        /// 鼠标按下事件        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void TipForm_MouseDown(object sender, MouseEventArgs e)        {            if (e.Button == MouseButtons.Left)            {                ptMouseDown = e.Location;            }        }        private void btnClose_Click(object sender, EventArgs e)        {            Close();        }        private void TipForm_SizeChanged(object sender, EventArgs e)        {            Point pt = new Point(ClientRectangle.X + ClientRectangle.Width - Radius / 4 - 32,                ClientRectangle.Y + Radius / 4);            btnClose.Location = pt;        }    }