[StructLayout(LayoutKind.Sequential)] 
public struct MARGINS 
{ 
  public int Left; 
  public int Right; 
  public int Top; 
  public int Bottom; 
} 
 
[DllImport("dwmapi.dll", PreserveSig = false)] 
static extern void DwmExtendFrameIntoClientArea(IntPtr hwnd, ref MARGINS margins); 
 
[DllImport("dwmapi.dll", PreserveSig = false)] 
static extern bool DwmIsCompositionEnabled(); 
 
public Form1() 
{ 
  InitializeComponent(); 
} 
 
protected override void OnLoad(EventArgs e) 
{ 
  if (DwmIsCompositionEnabled()) 
  { 
    MARGINS margins = new MARGINS(); 
    margins.Right = margins.Left = margins.Top = margins.Bottom = this.Width + this.Height; 
    DwmExtendFrameIntoClientArea(this.Handle, ref margins); 
  } 
  base.OnLoad(e); 
} 
 
protected override void OnPaintBackground(PaintEventArgs e) 
{ 
  base.OnPaintBackground(e); 
  if (DwmIsCompositionEnabled()) 
  { 
    e.Graphics.Clear(Color.Black); 
  } 
}