Question

Is there a way to tell whether my application is active i.e. any of its windows has .IsActive=true?

I’m writing messenger app and want it to flash in taskbar when it is inactive and new message arrives.

Answer 1

Used P/Invoke and loop

[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern IntPtr GetForegroundWindow();

private static bool IsActive(Window wnd)
{
    // workaround for minimization bug
    // Managed .IsActive may return wrong value
    if (wnd == null) return false;
    return GetForegroundWindow() == new WindowInteropHelper(wnd).Handle;
}

public static bool IsApplicationActive()
{
    foreach (var wnd in Application.Current.Windows.OfType<Window>())
        if (IsActive(wnd)) return true;
    return false;
}