Drop shadow in Winforms Controls?

问题:

is there a way to add a drop shadow to controls?

are there any controls out there with this feature?

回答1:

This question has been around for 6 years and needs an answer. I hope that anyone who needs to do this can extrapolate an answer for any control set from my solution. I had a panel and wanted to draw a drop shadow underneath every child control - in this instance one or more panels (but the solution should hold good for other control types with some minor code changes).

As the drop shadow for a control has to be drawn on the surface of that control's container we start by adding a function to the container's Paint() event.

Container.Paint += dropShadow;

dropShadow() looks like this:

    private void dropShadow(object sender, PaintEventArgs e)
    {
        Panel panel = (Panel)sender;
        Color[] shadow = new Color[3];
        shadow[0] = Color.FromArgb(181, 181, 181);
        shadow[1] = Color.FromArgb(195, 195, 195);
        shadow[2] = Color.FromArgb(211, 211, 211);
        Pen pen = new Pen(shadow[0]);
        using (pen)
        {
            foreach (Panel p in panel.Controls.OfType<Panel>())
            {
                Point pt = p.Location;
                pt.Y += p.Height;
                for (var sp = 0; sp < 3; sp++)
                {
                    pen.Color = shadow[sp];
                    e.Graphics.DrawLine(pen, pt.X, pt.Y, pt.X + p.Width - 1, pt.Y);
                    pt.Y++;
                }
            }
        }
    }

Clearly you can pick a different control type from the container's collection and you can vary the colour and depth of the shadow with some minor tweaks.

回答2:

You have to overwrite the CreateParamsproperty like this:

private const int CS_DROPSHADOW = 0x00020000;
protected override CreateParams CreateParams
{
    get
    {
        // add the drop shadow flag for automatically drawing
        // a drop shadow around the form
        CreateParams cp = base.CreateParams;
        cp.ClassStyle |= CS_DROPSHADOW;
        return cp;
    }
}

回答3:

There is in WPF if you can stretch to using that instead, I don't believe there is an alternative in Windows Forms due to the limited capabilities of GDI+.