Socket Programming

Question

Am trying to create a server application in c#.In the code am using the TcpListener class.

    TcpListener t = new TcpListener(5555);
    t.Start();

However it is providing an error saying: Invalid token '(' in class, struct, or interface member declaration.

Are there additional references required?.
Please help.

namespace WindowsApplication1
{
    public partial class lanmessenger : Form
    {
        [DllImport("user32.dll")]
        static extern bool HideCaret(IntPtr hWnd);

        public lanmessenger()
        {
            InitializeComponent();
        }


        private void textBox1_TextChanged(object sender, EventArgs e)
        {


        }
        private void button1_Click(object sender, EventArgs e)
        {
            StringBuilder sb = new StringBuilder(this.textBox1.Text);
            sb.AppendLine(this.textBox2.Text);
            this.textBox1.Text = sb.ToString();
            this.textBox2.Text = "\0";
            HideCaret(this.textBox1.Handle);
        }
        private void textBox1_MouseClick(object sender, MouseEventArgs e)
        {
            HideCaret(this.textBox1.Handle);
        }
        StreamWriter streamWriter;
        StreamReader streamReader;
        NetworkStream networkStream;
        TcpListener t = new TcpListener(5555);
        t.Start();




    }
}

This is the full source code upto now. Am unable to find the error.

Answer 1

Works fine for me. You need to add following line in your code.

using System.Net.Sockets;

Answer 2

Providing you have a reference to System.dll in your project and have a using statement for the System.Net.Sockets namespace, there is nothing wrong with the code you've provided.

It looks like you've got one too many '(' lying around somewhere.

Your call to t.Start() has to be in a method of the class. This is wrong:

class lanmessenger
{
    ...
    TcpListener t = new TcpListener(5555);  // ok to initialize like this
    t.Start();  // wrong...put this in a method
}

This is right:

class lanmessenger
{
    TcpListener t = new TcpListener(5555);  // ok to initialize like this

    public lanmessenger
    {
        InitializeComponent();
        t.Start();  // put it here
    }    
}

Answer 3

Don't you forget to put that code in some method of some class?

Answer 4

Yep, the problem here is just that this code is not inside a method within your class:

t.Start();

That's what's giving you the specific compiler error. You can't make a call to a method within a class itself, that has to be within some other method. The other stuff is fine where it is, syntactically speaking.

Answer 5

Are you sure you don't want to use WCF for a server app?

Answer 6

you can find a simple socket programming in C# from the following link

http://csharp.net-informations.com/communications/csharp-socket-programming.htm

bolton.