Timer control count down

You have to use dispatchertimer for that
DispatcherTimer timer = new DispatcherTimer();

timer.Tick += timer_Tick;
timer.Interval = TimeSpan.FromSeconds(1); //you can change timespan according to your choice.
timer.Start();

 void timer_Tick(object sender, object e)
{

      // Your code 

}

 Hope This is the answer of your question. 

use this 

 

 private void timer1_Tick(object sender, EventArgs e)         {             label1.Text = DateTime.Now.ToString();             second = second + 1;             if (second >= 10)             {                 timer1.Stop();                 MessageBox.Show("Exiting from Timer....");             }         }