c#透明panel

  public partial class PanelEx : Panel
    {
        protected Graphics graphics;

        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams cp = base.CreateParams;
                cp.ExStyle |= 0x00000020; // 实现透明样式

                return cp;
            }
        }
        public PanelEx()
        {
            InitializeComponent();
            this.BackColor = Color.Transparent;
            this.ForeColor = Color.Transparent;
        }
        protected override void OnPaintBackground(PaintEventArgs pevent)
        {

        }
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            this.graphics = e.Graphics;

            this.graphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
            this.graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;
            this.graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
            this.graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
            this.graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;

            if (this.BackgroundImage != null)
            {
                int width = this.Width;
                int height = this.Height;
                Rectangle recModel = new Rectangle(0, 0, width, height);
                this.graphics.DrawImage(this.BackgroundImage, recModel);
            }
            else if (this.ForeColor != Color.Transparent)
            {
                this.graphics.Clear(this.ForeColor);
            }

        }


    }