Get last active window: Get Previously active window

Question

I am working on an application which needs to get the last active window handle. Suppose my application is running then I want to get last active window handle that was just pre

Answer 1

I needed the same thing of the last handle from the previous window I had open. The answer from Jamie Altizer was close, but I modified it to keep from overwriting the previous window when my application gets focus again. Here is the full class I made with the timer and everything.

static class ProcessWatcher
{
    public static void StartWatch()
    {
        _timer = new Timer(100);
        _timer.Elapsed += new ElapsedEventHandler(timer_Elapsed);
        _timer.Start();
    }

    static void timer_Elapsed(object sender, ElapsedEventArgs e)
    {
        setLastActive();
    }

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

    public static IntPtr LastHandle
    {
        get
        {
            return _previousToLastHandle;
        }
    }

    private static void setLastActive()
    {
        IntPtr currentHandle = GetForegroundWindow();
        if (currentHandle != _previousHandle)
        {
            _previousToLastHandle = _previousHandle;
            _previousHandle = currentHandle;
        }
    }

    private static Timer _timer;
    private static IntPtr _previousHandle = IntPtr.Zero;
    private static IntPtr _previousToLastHandle = IntPtr.Zero;
}