I am trying to learn a little about socket programming and I have stumbled across TcpListener and TcpClient to use as I read they are slightly easier for beginners. The basic jist of what I want to accomplish is to have a small form that can be run on my laptop and another laptop on the same network and for them to be able to communicate i.e. send a string of text to each other. Once I have this I will hopefully develop it further :)
So far I have created both a Client and a Server program using msdn and various guides found on the internet. I can get them to communicate when both running on one laptop however when I move the client to another laptop I get nowhere. I think my main issue is I do not understand quite how the client finds the Servers IP as I think I could hard code it but when I come back at another time I'm sure the IP will have changed. Is there any way to get the two to connect in a more dynamic way to encompass the changing IP? My current Client code:
public void msg(string mesg)
{
lstProgress.Items.Add(">> " + mesg);
}
private void btnConnect_Click(object sender, EventArgs e)
{
string message = "Test";
try
{
// Create a TcpClient.
// Note, for this client to work you need to have a TcpServer
// connected to the same address as specified by the server, port
// combination.
Int32 port = 1333;
TcpClient client = new TcpClient(<not sure>, port); //Unsure of IP to use.
// Translate the passed message into ASCII and store it as a Byte array.
Byte[] data = System.Text.Encoding.ASCII.GetBytes(message);
// Get a client stream for reading and writing.
// Stream stream = client.GetStream();
NetworkStream stream = client.GetStream();
// Send the message to the connected TcpServer.
stream.Write(data, 0, data.Length);
lstProgress.Items.Add(String.Format("Sent: {0}", message));
// Receive the TcpServer.response.
// Buffer to store the response bytes.
data = new Byte[256];
// String to store the response ASCII representation.
String responseData = String.Empty;
// Read the first batch of the TcpServer response bytes.
Int32 bytes = stream.Read(data, 0, data.Length);
responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes);
lstProgress.Items.Add(String.Format("Received: {0}", responseData));
// Close everything.
stream.Close();
client.Close();
}
catch (ArgumentNullException an)
{
lstProgress.Items.Add(String.Format("ArgumentNullException: {0}", an));
}
catch (SocketException se)
{
lstProgress.Items.Add(String.Format("SocketException: {0}", se));
}
}
My current Server code:
private void Prog_Load(object sender, EventArgs e)
{
bw.WorkerSupportsCancellation = true;
bw.WorkerReportsProgress = true;
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
bw.ProgressChanged += new ProgressChangedEventHandler(bw_ProgressChanged);
if (bw.IsBusy != true)
{
bw.RunWorkerAsync();
}
}
private void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
lstProgress.Items.Add(e.UserState);
}
private void bw_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
if ((worker.CancellationPending == true))
{
e.Cancel = true;
}
else
{
try
{
// Set the TcpListener on port 1333.
Int32 port = 1333;
//IPAddress localAddr = IPAddress.Parse("127.0.0.1");
TcpListener server = new TcpListener(IPAddress.Any, port);
// Start listening for client requests.
server.Start();
// Buffer for reading data
Byte[] bytes = new Byte[256];
String data = null;
// Enter the listening loop.
while (true)
{
bw.ReportProgress(0, "Waiting for a connection... ");
// Perform a blocking call to accept requests.
// You could also user server.AcceptSocket() here.
TcpClient client = server.AcceptTcpClient();
bw.ReportProgress(0, "Connected!");
data = null;
// Get a stream object for reading and writing
NetworkStream stream = client.GetStream();
int i;
// Loop to receive all the data sent by the client.
while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
{
// Translate data bytes to a ASCII string.
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
bw.ReportProgress(0, String.Format("Received: {0}", data));
// Process the data sent by the client.
data = String.Format("I Have Received Your Message: {0}", data);
byte[] mssg = System.Text.Encoding.ASCII.GetBytes(data);
// Send back a response.
stream.Write(mssg, 0, mssg.Length);
bw.ReportProgress(0, String.Format("Sent: {0}", data));
}
// Shutdown and end connection
client.Close();
}
}
catch (SocketException se)
{
bw.ReportProgress(0, String.Format("SocketException: {0}", se));
}
}
}
As you can probably tell I am brand new to this so if there is a better way to implement this I am more than happy to learn! Thanks for any help in advance :)
My solution thanks to the answers below:
private String IPAddressCheck()
{
var IPAddr = Dns.GetHostEntry("HostName");
IPAddress ipString = null;
foreach (var IP in IPAddr.AddressList)
{
if(IPAddress.TryParse(IP.ToString(), out ipString) && IP.AddressFamily == AddressFamily.InterNetwork)
{
break;
}
}
return ipString.ToString();
}
private void btnConnect_Click(object sender, EventArgs e)
{
string message = "Test";
try
{
Int32 port = 1337;
string IPAddr = IPAddressCheck();
TcpClient client = new TcpClient(IPAddr, port);
I'm not sure if it is the neatest solution but it is working well so thank you for the answers :)