c# winform 重写button，让button变为椭圆的。

 public partial class ShapeButton : Button

    {

        public ShapeButton()

        {

            InitializeComponent();

        }

        protected override void OnPaint(PaintEventArgs pe)

        {

            base.OnPaint(pe);

        }

        bool flag;

        [Description(" 获取或设置按钮椭圆效果。"), DefaultValue(false)]

        public bool Circle

        {          

            set

            {

                flag = value;

                GraphicsPath gp = new GraphicsPath();

                gp.AddEllipse(this.ClientRectangle);//圆形

                this.Region = new Region(gp);

                FlatAppearance.BorderSize = 0;//去掉边框

                FlatStyle = System.Windows.Forms.FlatStyle.Flat;

                BackColor = System.Drawing.Color.FromArgb(((int)(((byte)(128)))), ((int)(((byte)(128)))), ((int)(((byte)(255)))));//背景颜色

                this.Invalidate();

            }

            get { return flag; }

        }

    }