Declare Auto Function FlashWindow Lib "User32" (ByVal hWnd As Int32, ByVal bInvert As Boolean) As Boolean

' True leaves the window in an inverse state.
' False flashes the window once and returns to normal.
Private Sub WindowFlash()
  FlashWindow(Me.Handle.ToInt32, True)
End Sub

Private Structure FLASHWINFO
    Dim cbSize As Int32     'Size of the structure in bytes
    Dim hwnd As Int32       'Handle to the window to be flashed
    Dim dwFlags As Int32    'Flash Status
    Dim uCount As Int32     'Number of times to flash the window. Ignored if flashing continuously.
    Dim dwTimeout As Int32  'Flash rate in milliseconds. Zero=default system flash rate.
End Structure

Const FLASHW_STOP As Int32 = &H0        'Stop Flashing
Const FLASHW_CAPTION As Int32 = &H1     'Flash Window Caption
Const FLASHW_TRAY As Int32 = &H2        'Flash Tray Button
Const FLASHW_ALL As Int32 = &H3         'Same as FLASHW_CAPTION + FLASHW_TRAY
Const FLASHW_TIMER As Int32 = &H4       'Flash continuously until the FLASHW_STOP flag is set
Const FLASHW_TIMERNOFG As Int32 = &HC   'Flash continuously until window comes to the foreground

Private Declare Auto Function FlashWindowEx Lib "User32" (ByRef pfwi As FLASHWINFO) As Boolean

Private Sub WindowFlash()
   Dim FI As FLASHWINFO
   With FI
       .cbSize = System.Runtime.InteropServices.Marshal.SizeOf(FI)
       .hwnd = Me.Handle.ToInt32
       .dwFlags = FLASHW_ALL + FLASHW_TIMERNOFG
       .uCount = 0
       .dwTimeout = 0
   End With
   FlashWindowEx(FI)
End Sub