C# Signature:

[DllImport("user32.dll")]
static extern int SetWindowRgn(IntPtr hWnd, IntPtr hRgn, bool bRedraw);

VB.NET Signature:

<DllImport("user32.dll")> _
Public Function SetWindowRgn(ByVal hWnd As Long, ByVal hRgn As IntPtr, ByVal bRedraw As Boolean) As Long
End Function

User-Defined Types:

None.

Notes:

None.

Tips & Tricks:

Please add some!

Rounded form:

[DllImport("user32.dll")]

static extern int SetWindowRgn(IntPtr hWnd, IntPtr hRgn, bool bRedraw);

[DllImport("gdi32.dll")]

static extern IntPtr CreateRoundRectRgn(int x1, int y1, int x2, int y2,int cx, int cy);

private void Form1_Load(object sender, System.EventArgs e)

{

SetWindowRgn (this.Handle, CreateRoundRectRgn ( 0, 0, 562, 257, 20, 20 ),true);

}

Sample Code:

Please add some!

Alternative Managed API:

You can use the TransparencyKey property on a Windows form to achieve the same effect.

You can also use the Region property of a Windows form to change the shape of the client area.