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  4. how to use thread in for loop in c#

how to use thread in for loop in c#

Scheduled Pinned Locked Moved C#
csharpperformancetutorialquestion
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  • L Lost User

    Ok, it's a little tricky. The simplest way, not very good is: make one thread for every ping action, start them all, then Join them all. Is that good enough for you? Otherwise, use ping.SendAsync, and make very sure that PingCompletedEventHandler is thread-safe. The handler will have to 1) save the result (safely! may involve locking) and 2) signal a waithandle (after saving the result). Then you can do a WaitAll over all the waithandles to continue when all the pings are done.

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    superselector
    wrote on last edited by
    #14

    if i follow the first option, Do in need to specify any timeout in Thread.Join method.

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    • S superselector

      if i follow the first option, Do in need to specify any timeout in Thread.Join method.

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      Lost User
      wrote on last edited by
      #15

      If the pings have a timeout, that should not be necessary, though it wouldn't be a problem either (as long as it's high enough to give the pings time to succeed).

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      • L Lost User

        If the pings have a timeout, that should not be necessary, though it wouldn't be a problem either (as long as it's high enough to give the pings time to succeed).

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        superselector
        wrote on last edited by
        #16

        i think i need to specify timeout in join with more that 2500 ms as i have specified a time out of 2 sec. without any time out its very slow.

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        • S superselector

          i think i need to specify timeout in join with more that 2500 ms as i have specified a time out of 2 sec. without any time out its very slow.

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          Lost User
          wrote on last edited by
          #17

          But sometimes the pings took 4 seconds, right?

          superselector wrote:

          without any time out its very slow.

          Well that's weird, it shouldn't take significantly longer than the longest running ping. Could you show the code?

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          • L Lost User

            But sometimes the pings took 4 seconds, right?

            superselector wrote:

            without any time out its very slow.

            Well that's weird, it shouldn't take significantly longer than the longest running ping. Could you show the code?

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            superselector
            wrote on last edited by
            #18

            yes the time out takes 4 secs, i have given 2 secs for testing ... actually on successful ping checking for ping i am trying to get some basic details of that ip using WMI.WMI is taking some time also if its not enabled.

            for (int index = startIP; index <= EndIP; index++)
            {
            ipVal = startSubnet + "." + index.ToString();

                           Thread wmithread = new Thread(() => PerformWMIOperation(ipVal.ToString().Trim(), txtUserName.Text.ToString().Trim(), txtPassword.Text.ToString(), txtDomain.Text.ToString(), dtAssetValues, chkImpersonate.Checked, recordnumber));
                            wmithread.Start();
                            wmithread.Join(2500);
                        }
            
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            • S superselector

              yes the time out takes 4 secs, i have given 2 secs for testing ... actually on successful ping checking for ping i am trying to get some basic details of that ip using WMI.WMI is taking some time also if its not enabled.

              for (int index = startIP; index <= EndIP; index++)
              {
              ipVal = startSubnet + "." + index.ToString();

                             Thread wmithread = new Thread(() => PerformWMIOperation(ipVal.ToString().Trim(), txtUserName.Text.ToString().Trim(), txtPassword.Text.ToString(), txtDomain.Text.ToString(), dtAssetValues, chkImpersonate.Checked, recordnumber));
                              wmithread.Start();
                              wmithread.Join(2500);
                          }
              
              L Offline
              L Offline
              Lost User
              wrote on last edited by
              #19

              Ok, not like that. Don't, "for every thread, start it, then join it". That just runs everything in serial. Do, "for every thread, start it. Then, for every thread, join it." That's how I said it: start them all then join them all.

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              • L Lost User

                Ok, not like that. Don't, "for every thread, start it, then join it". That just runs everything in serial. Do, "for every thread, start it. Then, for every thread, join it." That's how I said it: start them all then join them all.

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                superselector
                wrote on last edited by
                #20

                Hi i did not understand do you want the code to be changed to for (int index = startIP; index <= EndIP; index++) { ipVal = startSubnet + "." + index.ToString(); Thread wmithread = new Thread(() => PerformWMIOperation(ipVal.ToString().Trim(), txtUserName.Text.ToString().Trim(), txtPassword.Text.ToString(), txtDomain.Text.ToString(), dtAssetValues, chkImpersonate.Checked, recordnumber)); wmithread.Start(); wmithread.Join(); }

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                • S superselector

                  Hi i did not understand do you want the code to be changed to for (int index = startIP; index <= EndIP; index++) { ipVal = startSubnet + "." + index.ToString(); Thread wmithread = new Thread(() => PerformWMIOperation(ipVal.ToString().Trim(), txtUserName.Text.ToString().Trim(), txtPassword.Text.ToString(), txtDomain.Text.ToString(), dtAssetValues, chkImpersonate.Checked, recordnumber)); wmithread.Start(); wmithread.Join(); }

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                  Lost User
                  wrote on last edited by
                  #21

                  That wouldn't help. The problem is this:

                  superselector wrote:

                  wmithread.Start(); wmithread.Join();

                  That's like calling that ping operation without a thread, except this way resources are wasted as well. Or to put it differently, it's like hiring a team to play a game of monopoly, in order to do it faster. That doesn't work. If everyone takes turns anyway, you might as well do it by yourself. You need an array of threads. Fill the array, start them all, then, and only then, join them all. Besides, what's with the WMI stuff? Do you need something that the Ping class[^] can't do?

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                  • L Lost User

                    That wouldn't help. The problem is this:

                    superselector wrote:

                    wmithread.Start(); wmithread.Join();

                    That's like calling that ping operation without a thread, except this way resources are wasted as well. Or to put it differently, it's like hiring a team to play a game of monopoly, in order to do it faster. That doesn't work. If everyone takes turns anyway, you might as well do it by yourself. You need an array of threads. Fill the array, start them all, then, and only then, join them all. Besides, what's with the WMI stuff? Do you need something that the Ping class[^] can't do?

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                    superselector
                    wrote on last edited by
                    #22

                    can you please give a sample code to implement this

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                    • S superselector

                      can you please give a sample code to implement this

                      L Offline
                      L Offline
                      Lost User
                      wrote on last edited by
                      #23

                      Ok.. it's not that hard though.

                      Thread[] threads = new Thread[something];
                      for (int i = 0; i < threads.Length; i++)
                      {
                      threads[i] = new Thread(something);
                      threads[i].Start();
                      }
                      for (int i = 0; i < threads.Length; i++)
                      threads[i].Join();

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                      • L Lost User

                        Ok.. it's not that hard though.

                        Thread[] threads = new Thread[something];
                        for (int i = 0; i < threads.Length; i++)
                        {
                        threads[i] = new Thread(something);
                        threads[i].Start();
                        }
                        for (int i = 0; i < threads.Length; i++)
                        threads[i].Join();

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                        superselector
                        wrote on last edited by
                        #24

                        hi with this approach , I am missing data .. means i am not getting output for all the IPs

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                        • L Lost User

                          Ok.. it's not that hard though.

                          Thread[] threads = new Thread[something];
                          for (int i = 0; i < threads.Length; i++)
                          {
                          threads[i] = new Thread(something);
                          threads[i].Start();
                          }
                          for (int i = 0; i < threads.Length; i++)
                          threads[i].Join();

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                          superselector
                          wrote on last edited by
                          #25

                          The ip address is getting overlapped. Means two rows are having same ip address.

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                          • S superselector

                            The ip address is getting overlapped. Means two rows are having same ip address.

                            L Offline
                            L Offline
                            Lost User
                            wrote on last edited by
                            #26

                            Did you forget to use synchronization when saving the result?

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