Why this thread exits?

[GordonFreeman]

In a thread different from the main one, i am sending/receiving data to a socket and i am waiting the response via a callback, but the thread enters the "Stopped" state even if i'm waiting for pending operations to end, and this is strange because the callback functions are still executed on that thread, while it is "Stopped"!!

This is the main thread, where i create the new thread

                                                    // BeginRequestToMainServer defined later
            Thread t = new Thread(BeginRequestToMainServer); 
            t.Start();

            t.Join();

                /* when this Messagebox prints "Stopped", the callback functions on the t thread
                    keep executing!
                */
           MessageBox.Show("t state is " + t.ThreadState);

This is the separate thread:

        private void BeginRequestToMainServer()
        {
            try
            {
                socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                socket.BeginConnect(mainserveraddress, 80, new AsyncCallback(OnConnectToMainServer), null);
            }
            catch (Exception ex)
            {                
                socket.Close();
            }

          /*
             Here the thread procedure returns, and then the thread turns into the Stopped state, 
             but this should not happen because there is a pending asynchronous operation 
             in this thread!
             Indeed, the OnConnectToMainServer callback will be called later
         */

        } // end BeginRequestToMainServer
 


            /*
                OnConnectToMainServer will be executed even if the main thread has already exited
                the t.Join() call, and this thread is in the Stopped state
            */
        protected override void OnConnectToMainServer(IAsyncResult res)
        {
            // send post parameters to the page
            String vars = "param1=" + param1+ "&param2=" + param2;
            String postrequest = "POST /page.php HTTP/1.1\r\n" +
                                 "Host: " + mainserveraddress + "\r\n" +
                                 "Content-Length: " + vars.Length + "\r\n" +
                                 "Content-Type: application/x-www-form-urlencoded\r\n\r\n" +
                                 vars;

            try
            {
                socket.BeginSend(Encoding.ASCII.GetBytes(postrequest), 0, postrequest.Length, SocketFlags.None, new AsyncCallback(OnSendToMainServer), null);
            }
            catch (Exception ex)
            {
                socket.Close();
            }

        } // end OnConnectToMainServer


            /*
                OnSendToMainServer will be executed even if the main thread has already exited the
                t.Join() call, and this thread is in the Stopped state
            */
    protected override void OnSendToMainServer(IAsyncResult res){
        ........
    }

What is going on here?
That tread is dead but it executes the callbacks :O

At the end, what i want is to block the main thread until the other one ends the communication via the socket

[boudino]

Because in BeginRequestToMainServer you call Socket.BeginConnect(), which begins an asynchronous request for a remote host connection. That means, that call to BeginConnect() returns immediately which causes that BeginRequestToMainServer() returns immediately too and calling to Join() ends, displaying the message "Stopped".

[GordonFreeman]

Because in BeginRequestToMainServer you call Socket.BeginConnect(), which begins an asynchronous request for a remote host connection. That means, that call to BeginConnect() returns immediately which causes that BeginRequestToMainServer() returns immediately too and calling to Join() ends, displaying the message "Stopped".

ok ok i see: the Stopped state does not mean "the thread exited" , it is still alive but not executing the main procedure.
so the Join() returns after the thread procedure ends and not necessaily if the thread ends.

i solved using a Semaphore to force the thread procedure BeginRequestToMainServer to wait before returning to the caller, until the async callbacks end communicating via the socket.

[boudino]

The thread ends too, but BeginConnect() starts a new one. That's the point. To wait for it, use something like

IAsyncResult ar = socket.BeginConnect(...);
ar.WaitHandle.WaitOne();

[GordonFreeman]

The thread ends too, but BeginConnect() starts a new one. That's the point. To wait for it, use something like

IAsyncResult ar = socket.BeginConnect(...);
ar.WaitHandle.WaitOne();

i didn't know that, thank u!

[Mutant_Fruit]

Or just use socket.Connect (), it is the synchronous version

[GordonFreeman]

Or just use socket.Connect (), it is the synchronous version

As far as i know synchronous socket calls are not supported since .NET ver. 2.. or maybe that's true for Silverlight only ??