C#

			Bitmap bm = new Bitmap(...);<br />
			Color transparent = bm.GetPixel(0,0);<br />
			bm.MakeTransparent(transparent);<br />
<br />
			this.BackgroundImage = bm;

adrianna_r wrote:

If I understand your suggestion correctly, that code will make my panel transparent, but I want it to still be visible, but faded.

public partial class CustomPanel : Panel
{
    Color color;
    public CustomPanel()
    {
        InitializeComponent();
        color = Color.FromArgb(100, Color.Blue);
    }
    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams cp = base.CreateParams;
            cp.ExStyle |=  0x00000020; //WS_EX_TRANSPARENT
            return cp;
        }
    }

    protected override void OnPaintBackground(PaintEventArgs e){}

    protected override void OnPaint(PaintEventArgs e)
    {

        using (Brush brush = new SolidBrush(color))
        {
            e.Graphics.Clear(Color.Transparent);
            e.Graphics.FillRectangle(brush, this.ClientRectangle);
        }
    }
}