Flash Taskbar button when window is inactive or at background. Click button and minimize window to test this sample.
Public Class Form1 Public Structure FLASHWINFO Public cbSize As Int32 Public hwnd As IntPtr Public dwFlags As Int32 Public uCount As Int32 Public dwTimeout As Int32 End Structure Private Declare Function FlashWindowEx Lib "user32.dll" (ByRef pfwi As FLASHWINFO) As Int32 Public Const FLASHW_STOP = 0 ' Stop flashing. The system restores the window to its original state. Public Const FLASHW_CAPTION = &H1 ' Flash the window caption. Public Const FLASHW_TRAY = &H2 ' Flash the taskbar button. Public Const FLASHW_ALL = &H3 ' Flash both the window caption and taskbar button. Public Const FLASHW_TIMER = &H4 ' Flash continuously, until the FLASHW_STOP flag is set. Public Const FLASHW_TIMERNOFG = &HC ' Flash continuously until the window comes to the foreground. Public Sub FlashIcon(ByVal Handle%, ByVal Flags%) Dim flash As New FLASHWINFO flash.cbSize = System.Runtime.InteropServices.Marshal.SizeOf(flash) '/// size of structure in bytes flash.hwnd = Handle '/// Handle to the window to be flashed flash.dwFlags = Flags flash.dwTimeout = 500 '/// speed of flashes in MilliSeconds ( can be left out ) FlashWindowEx(flash) '/// flash the window End Sub Dim WithEvents tmr As New Timer Dim count As Integer = 0 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click tmr.Interval = 1000 tmr.Start() End Sub Private Sub test(ByVal sender As Object, ByVal e As EventArgs) Handles tmr.Tick If count >= 5 Then tmr.Stop() FlashIcon(MyBase.Handle, FLASHW_TRAY + FLASHW_TIMERNOFG) End If count += 1 End Sub End Class