How can I trigger an auto-logout within a Windows Forms Application?

Question

I have a Windows App Project to which users can login with their userid and passwords. I want to make it so that when a user logs in, I will get the Login Time, and if the u

Answer 1

This is the simple way to solve this problem. It's working well.

using System;
using System.Windows.Forms;
namespace WindowsApplication1 {
    public partial class Form1 : Form, IMessageFilter {
        private Timer mTimer;
        private int mDialogCount;
        public Form1() {
            InitializeComponent();
            mTimer = new Timer();
            mTimer.Interval = 2000;
            mTimer.Tick += LogoutUser;
            mTimer.Enabled = true;
            Application.AddMessageFilter(this);
        }

        public bool PreFilterMessage(ref Message m) {
            // Monitor message for keyboard and mouse messages
            bool active = m.Msg == 0x100 || m.Msg == 0x101;  // WM_KEYDOWN/UP
            active = active || m.Msg == 0xA0 || m.Msg == 0x200;  // WM_(NC)MOUSEMOVE
            active = active || m.Msg == 0x10;  // WM_CLOSE, in case dialog closes
            if (active) {
                if (!mTimer.Enabled) label1.Text = "Wakeup";
                mTimer.Enabled = false;
                mTimer.Start();
            }
            return false;
        }

        private void LogoutUser(object sender, EventArgs e) {
            // No activity, logout user
            if (mDialogCount > 0) return;
            mTimer.Enabled = false;
            label1.Text = "Time'z up";
        }

        private void button1_Click(object sender, EventArgs e) {
            mDialogCount += 1;
            Form frm = new Form2();
            frm.ShowDialog();
            mDialogCount -= 1;
            mTimer.Start();
        }
    }
}

Answer 2

Edit: Adam is absolutely right, I've misunderstood the question, so I deleted my original answer.

To monitor user activity, you could create a custom Form-based class from which your application forms will inherit. There you can subscribe to the MouseMove and KeyDown events (setting the KeyPreview property to true), either of which will be raised whenever the user is active. You can then create a System.Threading.Timer, with the due time set to 30 minutes, and postpone it using the Change() method whenever user activity is detected.

This is an example implementation below: the ObservedForm is written to be rather general, so that you can more easily see the pattern.

public class ObservedForm : Form
{
     public event EventHandler UserActivity;

     public ObservedForm()
     {
         KeyPreview = true;

         FormClosed += ObservedForm_FormClosed;
         MouseMove += ObservedForm_MouseMove;
         KeyDown += ObservedForm_KeyDown;
     }

     protected virtual void OnUserActivity(EventArgs e)
     {
         var ua = UserActivity;
         if(ua != null)
         {
              ua(this, e);
         }
     }

     private void ObservedForm_MouseMove(object sender, MouseEventArgs e)
     {
          OnUserActivity();
     }

     private void ObservedForm_KeyDown(object sender, KeyEventArgs e)
     {
          OnUserActivity();
     }

     private void ObservedForm_FormClosed(object sender, FormClosedEventArgs e)
     {
         FormClosed -= ObservedForm_FormClosed;
         MouseMove -= ObservedForm_MouseMove;
         KeyDown -= ObservedForm_KeyDown;
     }
}

Now you can subscribe to the UserActivity event, and do the logics you desire, for example:

private System.Threading.Timer timer = new Timer(_TimerTick, null, 1000 * 30 * 60, Timeout.Infinite);
private void _OnUserActivity(object sender, EventArgs e)
{
     if(timer != null)
     {
         // postpone auto-logout by 30 minutes
         timer.Change(1000 * 30 * 60, Timeout.Infinite);
     }
}

private void _TimerTick(object state)
{
    // the user has been inactive for 30 minutes; log him out
}

Hope this helps.

Edit #2: rephrased some parts of the explanation for clarity, and changed the use of the FormClosing event to FormClosed.

Answer 3

1.st: User logs in, store the timestamp somewhere (for example this unix timestamp '1294230230' says it's aproximately 5th January 2011, 12:24)
int sess_creation_time = now(); ^{*lets say 'now()' function returns current unix timestamp}

2.nd: when user tries to perform any action, catch the timestamp of this attempt.
int temp_time = now();
Now, simply compare these values with your desired auto logout limit.

// compare here
// a, temp_time - sess_creation_time => the difference, time of inactivity
// 60*30 -> 60 seconds * 30 -> 30 minutes
if( (temp_time - sess_creation_time) > (60*30) )
{
  // time of inactivity is higher than allowed, logout here
  logout();
}
else
{
  // session is still valid, do not forget to update its creation time
  sess_creation_time = now();
}

Do not forget, this is not written in C/C++ or C#, but the logic remains the same ;-)
Hope, this helps you a bit

Answer 4

You have to make a base class for all your Forms, that will intercept any user activity and store the last activity time. Each time user clicks sth you would have to check the last activity date and decide whether it was too long ago, or not.

At the moment I have no idea how to intercept, but I'm pretty sure it's possible (maybe using windows messages?)