C# Winforms Irregular Windows

Question

How do I create windows with irregular shapes using WinForms and C#?

Answer 1

Have a look at this question.
http://stackoverflow.com/questions/176720/irregular-shaped-windows-form-c

Answer 2

There are a few different ways to achieve this. One is use use TransparencyKey (as in the post pointed out by Nifle). Another one is to assign a Region object to the Region property of the form:

System.Drawing.Drawing2D.GraphicsPath path = new System.Drawing.Drawing2D.GraphicsPath();
path.AddPolygon(new[]
{
    new Point(20, 20),
    new Point(40, 10),
    new Point(180, 70),
    new Point(160, 260),
    new Point(80, 140)
});
path.AddEllipse(40, 40, 300, 300);
this.Region = new Region(path);

Note that the coordinates refer to the window, not the client area. Also note how overlapping figures in the GraphicsPath object "invert" each other by default (this can be prevented by setting path.FillMode = FillMode.Winding).