public MyTransparentControl()

        {

            InitializeComponent();

           

            SetStyle(ControlStyles.SupportsTransparentBackColor



              | ControlStyles.UserPaint



              | ControlStyles.AllPaintingInWmPaint



              | ControlStyles.Opaque, true);



 

            base.CreateControl();

            

            this.BringToFront();

        }



protected override void OnPaint(PaintEventArgs e)

        {

            base.OnPaint(e);



            for (int i = 0; i < this.Width; i += 100)//画线

            {

                e.Graphics.DrawLine(new Pen(Color.Gray), new Point(i + 50, 0), new Point(i, this.Height - 1));

            }

        }



        protected override CreateParams CreateParams

        {

            get

            {

                CreateParams cp = base.CreateParams;

                

                cp.Style |= 0x00000020;

                //WS_EX_TRANSPARENT