Add count down to data grid view every time button is pressed. Then delete row after countdown reaches 0

Question

I'm attempting to add a countdown to a data grid view which goes from 2 minutes to 0. When the button is pressed it should add a new row with a token and a 2 minute countdown. When the 2 minute countdown reaches 0 that row should be deleted. I have the token already set up and at the moment instead of a countdown I'm using time in 2 minutes. The main thing I want to achieve is deleting the token after 2 minutes which is when the token expires.

Here's my current code:

        //Add Token To Grid
        int row = 0;
        TokenGrid.Rows.Add();
        row = TokenGrid.Rows.Count - 2;
        TokenGrid["CaptchaToken", row].Value = CaptchaWeb.Document.GetElementById("gcaptcha").GetAttribute("value");
        //Time Left
        TokenGrid["ExpiryTime", row].Value = DateTime.Now.AddMinutes(2).ToLongTimeString();

Answer 1

In timer's timeelapsed() event, compare the value ExpiryTime of each row with current time. If ExpiryTime < current time , delete the row.

Answer 2

Implement a timer (see How do I create a timer in WPF? ):

const int MAX_DURATION = 120;
System.Windows.Threading.DispatcherTimer dispatcherTimer;

// In the OnClick
DateTime timerStart = DateTime.Now;
dispatcherTimer = new System.Windows.Threading.DispatcherTimer();
EventHandler handler = new EventHandler(dispatcherTimer_Tick);
dispatcherTimer.Tick += handler;
dispatcherTimer.Interval = TimeSpan.FromSeconds(1);
dispatcherTimer.Start();

private void dispatcherTimer_Tick(object sender, EventArgs e)
{
     // Display seconds 
     var currentValue = DateTime.Now - timerStart; 
     TokenGrid["ExpiryTime", row].Value = currentValue.Seconds.ToString();

     // When the MAX_DURATION (2 minutes) is reached, stop the timer
     if (currentValue >= MAX_DURATION) {
         dispatcherTimer.Tick -= handler;
         dispatcherTimer.Stop();
         TokenGrid.Rows.RemoveAt(row);
     }
}