Visual Basic 2008 Winsock Chat

coldfire417 · #1 (**permalink**) 06-20-2009, 4:09 AM

Hey, I was wondering how I could actually make a WORKING chat system in visual basic 2008. I've watched tutorials on YouTube, and all of them fail and I get a weird error. I wan't one were you simply put in your buddie's IP and they put in yours and you can talk. A attachment or download link or project sample would be nice

...or code

Thanks!

JohnH · #2 (**permalink**) 06-20-2009, 10:14 AM

Learn about TcpClient and TcpListener. To connect something need to be listening at the other end, a server, that is the job of the TcpListener. To start one create an instance where you specify which ip and port to listen from and call the Start method, keep it in a class variable. This is then needed at minimum at server:

Code:

Private server As TcpListener

Code:

server = New TcpListener(ip, port)
server.Start()

The server ip is the local IP address you wish to bind to, here's an example retrieving it:

Code:

Dim localIP As Net.IPAddress = Net.Dns.GetHostAddresses("")(0)

With a Timer you can check Pending property to see if a client is attempting to connect, then AcceptTcpClient to establish the connection:

Code:

If server.Pending Then
    client = server.AcceptTcpClient

The 'client' you can also keep in a class variable, it's functionality is same as described below for communication.

Code:

Private client As TcpClient

At client you can connect to the server with a TcpClient:

Code:

Private client As TcpClient

Code:

client = New TcpClient(ip, port)

For basic communication sending strings it is most convenient using StreamWriter/StreamReader, these can read/write via the NetworkStream of the TcpClient, keep them in class variables:

Code:

Private reader As IO.StreamReader
Private writer As IO.StreamWriter

initialize them after connection is made:

Code:

reader = New IO.StreamReader(client.GetStream)
writer = New IO.StreamWriter(client.GetStream)
writer.AutoFlush = True

Now you can write messages with a call to WriteLine method:

Code:

writer.WriteLine("message")

and read with ReadLine method if data is available, use a Timer to check this at intervals:

Code:

If client.GetStream.DataAvailable Then
    Dim msg As String = reader.ReadLine

The server and client functionality can be built into each client, so each client has the ability to receive connections. The server can also be a dedicated application that all clients connect to.

Finally I will mention cleanups, the server listener is closed with a call to Stop method:

Code:

server.Stop()

The sockets is closed by closing the NetworkStream of TcpClient

Code:

client.GetStream.Close()

Since this example uses stream-reader/writer you can also close the socket by closing/disposing the reader/writer:

Code:

reader.Dispose()
writer.Dispose()

The TcpClient is released by calling Close method:

Code:

client.Close()

Hope this brief introduction to sockets help.

You will also need to use Try-Catch with several of these calls, as they may and will throw exceptions. Reading the documentation and trying out things will help you understand this.

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