Periodically checking for 5 seconds using Stopwatch in C#

Question

I want to periodically check for 60 s in C#. I was able to do it by checking the date periodically as follows

However, when I use the stopwatch, the stopwatch resets back to the beginning instead of continuing from the previous time the stopwatch was stopped.

using System;
using System.Diagnostics;
using System.Threading;

namespace StopwatchExample
{
    class Program
    {
        static void Main()
        {
            ////Works
            //DateTime start = DateTime.Now;
            //while (true)
            //{
            //    DateTime current = DateTime.Now;
            //    var diffInSeconds = (current - start).TotalSeconds;
            //    if (diffInSeconds > 5)
            //    {
            //        Console.WriteLine("5 s done!");
            //        break;
            //    }
            //}

            // Does not work
            Stopwatch stopwatch = new Stopwatch();
            stopwatch.Start();
            while (true)
            {
                stopwatch.Stop();
                if (stopwatch.Elapsed.Seconds > 5)
                {
                    Console.WriteLine("5 s done!");
                    break;
                }
                else
                {
                    stopwatch.Start();
                }
            }

            Console.ReadLine();
        }
    }
}

Answer 1

As others have said, a Timer is probably the better solution. Given your usage of Stopwatch, you need to change your logic to this:

        Stopwatch stopwatch = new Stopwatch();
        stopwatch.Start();
        while (true)
        {
            // Check elapsed time w/o stopping/resetting the stopwatch
            // May want to include the 5 seconds themselves (>= instead of >)
            if (stopwatch.Elapsed.Seconds >= 5)
            {
                // At least 5 seconds elapsed, restart stopwatch.
                stopwatch.Stop();
                stopwatch.Start();
                Console.WriteLine("5 s done!");
                // Not sure about this, if you really want to check "periodically",
                // this break makes less sense, because the checking
                // logic will stop after the first 5 seconds have elapsed.
                break;
            }
        }

Answer 2

Try to use Timer (System.Timers) instead of Stopwatch. Set the required interval and perform the necessary actions on Elapsed event.

Here you can find out more.

Example:

public static void Main()
{
    // Create a timer and set a two second interval.
    aTimer = new System.Timers.Timer();
    aTimer.Interval = 2000; // 2000ms == 2s

    // Hook up the Elapsed event for the timer. 
    aTimer.Elapsed += OnTimedEvent;

    // Have the timer fire repeated events (true is the default)
    aTimer.AutoReset = true;

    // Start the timer
    aTimer.Enabled = true;

    Console.WriteLine("Press the Enter key to exit the program.");
    Console.ReadLine();
}

private static void OnTimedEvent(Object source, System.Timers.ElapsedEventArgs e)
{
    Console.WriteLine("The interval has been elapsed");
}