MessageBox with timeout (c#)

messagebox_timeout.cs

[DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName);

[DllImport("user32.Dll")]
static extern int PostMessage(IntPtr hWnd, UInt32 msg, int wParam, int lParam);

public static void MessageBox(string Text, string Caption = "", int timeOut = 0)
{
  if (Caption.Length == 0)
    Caption = "MessageBox";
  if (timeOut <= 0)
    {
      MessageBox.Show(Text, Caption, MessageBoxButtons.OK, MessageBoxIcon.Error);
      return;
    }

    Caption += " " + string.Format("{0:X4}", DateTime.Now.Millisecond); // Force unique Window Caption
    var timer = new System.Timers.Timer(5000) { AutoReset = false };
    timer.Elapsed += delegate
      {
        const UInt32 WM_CLOSE = 0x0010;
        IntPtr hWnd = FindWindowByCaption(IntPtr.Zero, Caption);
        if (hWnd.ToInt32() != 0) PostMessage(hWnd, WM_CLOSE, 0, 0);
      };
    timer.Enabled = true;
    MessageBox.Show(Text, Caption, MessageBoxButtons.OK, MessageBoxIcon.Error);

}