测试Tcp连接错误的线程

Question

I try to test Socket Connection. It show error

Cannot access a disposed object. Object name: 'System.Net.Sockets.TcpClient'.

at Connect(ip,port).

       System.Net.Sockets.TcpClient client = new TcpClient();
        try
        {
            System.Threading.Thread t = new System.Threading.Thread(() =>
        {
            client.Connect(ip,port );

        });
            t.Start();
        }
        catch (SocketException ex)
        {


        }
        catch (Exception ex) {

        }
        finally
        {
            client.Close();
        }

Answer 1

This is a race condition between the thread you start here:

    System.Threading.Thread t = new System.Threading.Thread(() =>
    {

        client.Connect(ip,port );

    });
    t.Start();

and the finally block here:

    finally
    {
        client.Close();
    }

In this case the main thread reached the finally block before your connection was finished.

Object creation and clean up really should be on the same thread, so try something like this unless you really need the closure.

System.Threading.Thread t = new System.Threading.Thread(() =>
{
    using(TcpClient client = new TcpClient())
    {
        client.Connect(ip, port);
        //followup code here
    }

});
t.Start();

Answer 2

depending on what you are trying to achieve, you can modify the code to

System.Threading.Thread t = new System.Threading.Thread(() =>
                {
                    using (System.Net.Sockets.TcpClient client = new TcpClient())
                    {
                        client.Connect("127.0.0.1", 80);
                        // Communicate with the Server. 
                    }   // The client object would be disposed here
                });
                t.Start();

Remember this code would create a new instance of TcpClient each time the thread would run. I am assuming, you would communicate with the server soon after establishing the connection and can then safely dispose the object, once its done.