[C#] AutoResetEvent Freezing application!

[litewarez]

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

namespace SimplePinger
{
    public partial class Form1 : Form
    {
        #region Variables

        int PingAmount = 5;
        AutoResetEvent Waiter = new AutoResetEvent(false);
        Ping pingSender = new Ping();
        PingOptions options = new PingOptions(64, true);
        #endregion

        public Form1()
        {
            InitializeComponent();
            updatePingValue(5); //Set defualt to 5
        }

        private void PingTimes_Scroll(object sender, EventArgs e)
        {
            updatePingValue(PingTimes.Value);
        }

        private void updatePingValue(int Value)
        {
            PingAmount = PingTimes.Value;
            PingAmountLabel.Text = "Pings to send: " + PingAmount;
        }

        private void startPing_Click(object sender, EventArgs e)
        {
            DisableFormElements();
            outputBox.Clear();

            options.DontFragment = true;

            pingSender.PingCompleted += new PingCompletedEventHandler(PingCallback);

            //Create 32 byts to send
            byte[] buffer = Encoding.ASCII.GetBytes("                               ");
            int i;
            for (i = 0; i < PingAmount; i++)
            {


                //Here i want to run this 5 times but without the app freezing :(


                pingSender.SendAsync(addressBox.Text, 120, buffer, options);


            }
            Waiter.WaitOne();
            EnableFormElements();
        }

        public void PingCallback(object sender, PingCompletedEventArgs e)
        {
            if (e.Cancelled)
            {
                EnableFormElements();
            }

            if (e.Error != null)
            {
                MessageBox.Show("Ping Failed:" + e.Error.ToString());

                // Let the main thread resume. 
                ((AutoResetEvent)e.UserState).Set();
            }

            PingReply reply = e.Reply;
            Waiter.Set();
            AddCallbackToForm(reply);
        }

        public void AddCallbackToForm(PingReply Reply)
        {
            if (Reply == null)
            {
                return;
            }
            if (Reply.Status == IPStatus.Success)
            {
                outputBox.Text += "Success: " + Reply.Address + " - " + Reply.RoundtripTime + "ms";
            }
            else 
            {
                outputBox.Text += "Failed...";
            }

        }

        public void EnableFormElements()
        {
            startPing.Enabled = true;
            PingTimes.Enabled = true;
        }

        public void DisableFormElements()
        {
            startPing.Enabled = false;
            PingTimes.Enabled = false;
        }
    }
} 

here is the Form Class, seems to be freezing / hanging for a while and im sure its something Very stupid but every tutorial that i read shows me that im doing it right

Hope you can spot my error

litewarez Reviewed by litewarez on 8th Jul 2010. [C#] AutoResetEvent Freezing application! using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Net; using System.Net.NetworkInformation; Rating: 5

[Angeix]

Hello,

You should add some mutex locks in there, since it looks like there is some threading try adding some mutex locks and debug_log messages to check for the errros..

Best of luck...

[litewarez]

thanks for the advice but i don't think that's the case.

If i remove the Waiter, the applications does not freeze but just throws an error to say that i cant run 2 pings at the same time. So i need the waiter.

If you can show me how to multiple thread it i will give it a go !

ive tried the following just:

            for (i = 0; i <= PingAmount; i++)
            {
                Action Action = new Action(() => pingSender.SendAsync(addressBox.Text, 120, buffer, options));
                new Thread(new ThreadStart(Action));
            } 

And its stopped hangineg but now the textarea is not being updated

[Angeix]

Once you Multi threaded it you need to follow a guide for mutex locks otherwise your going to get a race condition..

[litewarez]

can you give me an example. and check my last post i edited it

[Angeix]

http://www.albahari.com/threading/part2.aspx

[Hyperz]

pingSender.SendAsync() shouldn't be executed from a new thread since SendAsync will not block the calling thread. It puts it on the thread pool automatically.

Also for a 32 byte buffer:
byte[] buffer = new byte[32];

Finally, get rid of AutoResetEvent. I have never used it, I don't see why you should need it for a simple async ping request.

@Angeix: locks aren't needed here.

[Angeix]

Am no good with C#

Learning vb.net myself mainly good with C++ with past experience with game server emulators

[Hyperz]

From C++ to VB? Why not C# then? VB is the ugly duck of the programming world .

[Angeix]

I love vb.net works quite well.