timer elspsed even after timing stop

Question

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Linq;

using System.Text;
using System.Threading.Tasks;
using System.Timers;

using System.Collections;
using System.Configuration;
using System.Xml;

namespace WindowsFormsApplication8
{
public partial class Form1 : Form
{
System.Timers.Timer RefObject;
public Form1()
{
InitializeComponent();
}

    private void Form1_Load(object sender, EventArgs e)
    {

    }

    private void button1_Click(object sender, EventArgs e)
    {
        CreateTimer();
    }

    private void CreateTimer()
    {
        System.Timers.Timer tmrSync = new System.Timers.Timer();
        RefObject = tmrSync;
        tmrSync.Interval = 3000;
        tmrSync.Elapsed += new ElapsedEventHandler(timerSync_Tick);
        tmrSync.Enabled = true;
        tmrSync.Start();
    }



    private void DisposeTimer()
    {

        RefObject.Enabled = false;
        RefObject.Stop();
    }

    private void timerSync_Tick(object sender, EventArgs e)
    {
        try
        {


            RefObject.Elapsed -= new ElapsedEventHandler(timerSync_Tick);
            textBox1.Text += "Secondhit " + Environment.NewLine;

            DisposeTimer();

            //Perform Operation
            textBox1.Text += "Hit " + Environment.NewLine;
            Application.DoEvents();
            CreateTimer();
        }
        catch (Exception)
        {
            DisposeTimer();
        }
    }
}

}

Answer 1

Here is an alternate approach.

Timer code is outside of a form, an event in this case pushes simple text to a caller of this class.

Start and Stop methods do just that, start and stop the Timer.

using System.Threading;
using Timer = System.Threading.Timer;

namespace WorkingWithTimer.Classes
{
    public class Utilities
    {
        /// <summary>
        /// How long between intervals, adjust as needed or use Initialize overload
        /// </summary>
        private static int _dueTime = 6000 * 10;
        private static Timer _workTimer;

        public delegate void MessageHandler(string message);
        /// <summary>
        /// Optional event
        /// </summary>
        public static event MessageHandler Message;
        /// <summary>
        /// Flag to determine if timer should initialize 
        /// </summary>
        public static bool ShouldRun { get; set; } = true;

        private static void Initialize()
        {
            if (!ShouldRun) return;

            _workTimer = new Timer(Dispatcher);
            _workTimer.Change(_dueTime, Timeout.Infinite);
        }

        private static void Initialize(int dueTime)
        {
            if (!ShouldRun) return;
            _dueTime = dueTime;
            _workTimer = new Timer(Dispatcher);
            _workTimer.Change(_dueTime, Timeout.Infinite);
        }
        private static void Dispatcher(object e)
        {
            Worker();
            _workTimer.Dispose();
            Initialize();
        }

        public static void Start()
        {
            Initialize();
            Message?.Invoke("Started");
        }
        public static void Stop()
        {
            _workTimer.Dispose();
            Message?.Invoke("Stopped");
        }

        /// <summary>
        /// Where work is done
        /// </summary>
        private static void Worker()
        {
            Message?.Invoke("Performing work");
        }

    }
}

In form load

Utilities.Message += OnMessageReceived;

Event for above

private void OnMessageReceived(string message) 
    => listBox1.InvokeIfRequired(lb => lb.Items.Add(message));

Extension method for above

public static class Extensions
{
    public static void InvokeIfRequired<T>(this T control, Action<T> action) where T : ISynchronizeInvoke
    {
        if (control.InvokeRequired)
        {
            control.Invoke(new Action(() => action(control)), null);
        }
        else
        {
            action(control);
        }
    }
}

Full code
https://github.com/karenpayneoregon/windows-forms-csharp/tree/Version3/WorkingWithTimer

Answer 2

Try using the System.Windows.Forms.Timer and remove the DoEvents line.

Since you call CreateTimer, a new timer is recreated. (Maybe you should use a single timer).