C# Signature:

[DllImport("user32.dll")]
static extern bool RedrawWindow(IntPtr hWnd, [In] ref RECT lprcUpdate, IntPtr hrgnUpdate, RedrawWindowFlags flags);

[DllImport("user32.dll")]
static extern bool RedrawWindow(IntPtr hWnd, IntPtr lprcUpdate, IntPtr hrgnUpdate, RedrawWindowFlags flags);

VB.NET Signature:

<DllImport("user32.dll")> _
Private Shared Function RedrawWindow(hWnd As IntPtr, <[In]> ByRef lprcUpdate As RECT, hrgnUpdate As IntPtr, flags As RedrawWindowFlags) As Boolean
End Function

<DllImport("user32.dll")> _
Private Shared Function RedrawWindow(hWnd As IntPtr, lprcUpdate As IntPtr, hrgnUpdate As IntPtr, flags As RedrawWindowFlags) As Boolean
End Function

User-Defined Types:

RECT, RedrawWindowFlags

Tips & Tricks:

Please add some!

Sample Code:

    private void InvalidateWindow()
    {
        WinAPI.RedrawWindow(this.Handle, IntPtr.Zero, IntPtr.Zero,
         0x0400/*RDW_FRAME*/ | 0x0100/*RDW_UPDATENOW*/
         | 0x0001/*RDW_INVALIDATE*/);
    }

Alternative Managed API:

Do you know one? Please contribute it!