/// <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 = ;

        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(-, -);

            GraphicsPath border = GetTipPath(rect);

            GraphicsPath curve = new GraphicsPath();

            graph.DrawPath(new Pen(Color.Black,), 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 / ,

                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, , -);

            path.AddArc(rect.X, rect.Y + height - Radius, Radius, Radius,

                , -);

            path.AddLine(

                new Point(rect.X + Radius / , rect.Y + height),

                new Point(rect.X + rect.Width /  - Radius / ,

                    rect.Y + height));

            path.AddLine(

               new Point(rect.X + rect.Width /  - Radius / ,

                   rect.Y + height),

               new Point(rect.X + rect.Width / , rect.Y + height + Radius));

            path.AddLine(

               new Point(rect.X + rect.Width / , rect.Y + height + Radius),

               new Point(rect.X + rect.Width /  + Radius / ,

                   rect.Y + height));

            path.AddLine(

                new Point(rect.X + rect.Width /  + Radius / ,

                    rect.Y + height),

                new Point(rect.X + rect.Width - Radius / ,

                    rect.Y + height));

            path.AddArc(rect.X + rect.Width - radius,

                rect.Y + height - Radius, Radius, Radius, , -);

            path.AddArc(rect.X + rect.Width - Radius, rect.Y,

                Radius, Radius, , -);

            path.AddLine(new Point(rect.X + rect.Width - Radius / , rect.Y),

                new Point(rect.X + Radius / , 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 /  - ,

                ClientRectangle.Y + Radius / );

            btnClose.Location = pt;

        }

    }