return a value from other thread?

92 New Member

okay so i have this situation:
i have to get round trip time (ping) from a IP, but if i do it in the UI thread it freezes if the ping is high, for example > 300, now to stop the UI to hang i made the ping in another thread, but how can i return value from the 2nd thread(the one pinging)?, i cant directly change the label because this code is in a dll, also even if i use delegates to make new thread (that support return value) the first thread wont stop for 2nd thread to give the return value, if i use thread.join then the whole idea of making ping in 2nd thread is useless because it just joines the 1st thread and freeze it...

any helps?

Sep 18 '09 #1

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6078

GaryTexmo

1,501

Recognized Expert Top Contributor

I'm not 100% sure so I'll just throw this out there...

Have your ping thread call the delegate when it's done, then have the main thread, when it receives that call, update the label. The form runs normally.

Nothing should have to wait on anything, it just updates when it gets the call.

Does that make any sense? If you've tried that and it doesn't work, then sorry. I haven't done much work with delegates, but this seems like any other event driven process. The main form should update when it gets the data, but it shouldn't need to wait on it.

Sep 18 '09 #2

vishal1082

New Member

as i said, the code is in a DLL, so i just dont have a label here, i dont want the form calling for ping request to freeze

and once again gary, u r the one helping me, suspicious how always u help me.. lol

Sep 19 '09 #3

GaryTexmo

1,501

Recognized Expert Top Contributor

Suspicious? Nah... maybe I just troll this forum too much ;)

Anyway, are you saying the code to the ping program is in a DLL? If so, you should still be able to create a thread to run the ping process, then call a delegate when it returns.

Can you please provide more details?

Sep 19 '09 #4

vishal1082

New Member

well actually nvm it, i spent a hour while i was sleepy cuz i was up all night and wrote this code, works exactly as i want, it may look noobish or ugly cuz i wrote it at 7 AM waking all night...

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         /// <summary>

        /// Ping a web address or IP

        /// </summary>

        public sealed class Ping

        {

            #region variables & objects

            Label lbl;

            Form owner;

            bool Continue = true;

            string address = null;

            #endregion
 
            #region constructor

            /// <summary>

            /// Ping a web address or IP

            /// </summary>

            /// <param name="Address">The Web Address or IP Address</param>

            /// <param name="Caller">The Form that is calling this class</param>

            public Ping(string Address, Form Caller)

            {

                address = Address;

                owner = Caller;

                ThreadStart starter = delegate { pingip(); };

                Thread pinger = new Thread(starter);

                pinger.Start();

            }

            #endregion
 
            #region events
 
            #region events

            void lbl_TextChanged(object sender, EventArgs e)

            {

                string[] pingip = lbl.Text.Split('|');

                try { owner.Invoke((MethodInvoker)delegate { try { PingResult(Convert.ToInt32(pingip[0]), pingip[1]); } catch { } }); }

                catch { }

            }

            #endregion
 
            #region custom events

            #region handlers

            /// <summary>

            /// PingResult Event Handler

            /// </summary>

            /// <param name="Ping">The ping result</param>

            /// <param name="IP">IP being pinged</param>

            public delegate void PingHandler(int Ping, string IP);

            /// <summary>

            /// Error Event Handler

            /// </summary>

            public delegate void ErrorHandler(Exception ex);

            #endregion
 
            #region event declare

            /// <summary>

            /// Event raised when we get result of the ping.

            /// </summary>

            public event PingHandler PingResult;

            /// <summary>

            /// Event raised when some error occurs.

            /// </summary>

            public event ErrorHandler OnError;

            #endregion

            #endregion
 
            #endregion
 
            #region methods
 
            #region public

            /// <summary>

            /// Stop pinging the address given

            /// </summary>

            public void StopPing()

            {

                Continue = false;

            }

            #endregion
 
            #region private

            private void pingip()

            {

                try

                {

                    lbl = new Label();

                    lbl.TextChanged += new EventHandler(lbl_TextChanged);

                    while (Continue)

                    {

                        System.Net.NetworkInformation.Ping ping = new System.Net.NetworkInformation.Ping();

                        PingReply reply = ping.Send(address);

                        try { lbl.Text = reply.RoundtripTime.ToString() + "|" + reply.Address.ToString(); }

                        catch { lbl.Text = reply.RoundtripTime.ToString() + "|Error getting IP"; }

                    }

                    return;

                }

                catch (Exception ex) { owner.Invoke((MethodInvoker)delegate { try { OnError(ex); } catch { } }); }

            }

            #endregion
 
            #endregion

        }

Sep 19 '09 #5

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