C# - Client/Server Broadcast Example 1

This code snippet demonstrates how to broadcast messages to all connected clients. The server listens for incoming connections. Each connection is handled by a new thread. The server maintains a list of all connected clients in an array. When a client sends a message to the server, the thread responsible for that client then sends the message to all clients except for it's self. Run the server first then load multiple client instances.

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Client

1. using System;  
2. using System.Collections.Generic;  
3. using System.Net;  
4. using System.Net.Sockets;  
5. using System.IO;  
6. using System.Text;  
7. using System.Threading;  
8.  
9. namespace Client  
10. {  
11.     class Program  
12.     {  
13.         static void Main(string[] args)  
14.         {  
15.             try  
16.             {  
17.                 TcpClient tcpClient = new TcpClient("127.0.0.1", 1234);  
18.                 Console.WriteLine("Connected to server.");  
19.                 Console.WriteLine("");  
20.  
21.                 Thread thread = new Thread(Read);  
22.                 thread.Start(tcpClient);  
23.  
24.                 StreamWriter sWriter = new StreamWriter(tcpClient.GetStream());  
25.  
26.                 while (true)  
27.                 {  
28.                     if (tcpClient.Connected)  
29.                     {  
30.                         string input = Console.ReadLine();  
31.                         sWriter.WriteLine(input);  
32.                         sWriter.Flush();  
33.                     }  
34.                 }  
35.  
36.             }  
37.             catch (Exception e)  
38.             {  
39.                 Console.Write(e.Message);  
40.             }  
41.  
42.             Console.ReadKey();  
43.         }  
44.  
45.         static void Read(object obj)  
46.         {  
47.             TcpClient tcpClient = (TcpClient)obj;  
48.             StreamReader sReader = new StreamReader(tcpClient.GetStream());  
49.  
50.             while (true)  
51.             {  
52.                 try  
53.                 {  
54.                     string message = sReader.ReadLine();  
55.                     Console.WriteLine(message);  
56.                 }  
57.                 catch (Exception e)  
58.                 {  
59.                     Console.WriteLine(e.Message);  
60.                     break;  
61.                 }  
62.             }  
63.         }  
64.     }  
65. } 

Server

1. using System;  
2. using System.Collections.Generic;  
3. using System.Net;  
4. using System.Net.Sockets;  
5. using System.IO;  
6. using System.Text;  
7. using System.Threading;  
8.  
9. namespace Server  
10. {  
11.     class Program  
12.     {  
13.         private static TcpListener tcpListener;  
14.         private static List<TcpClient> tcpClientsList = new List<TcpClient>();  
15.  
16.         static void Main(string[] args)  
17.         {  
18.             tcpListener = new TcpListener(IPAddress.Any, 1234);  
19.             tcpListener.Start();  
20.  
21.             Console.WriteLine("Server started");  
22.  
23.             while (true)  
24.             {  
25.                 TcpClient tcpClient = tcpListener.AcceptTcpClient();  
26.                 tcpClientsList.Add(tcpClient);  
27.  
28.                 Thread thread = new Thread(ClientListener);  
29.                 thread.Start(tcpClient);  
30.             }  
31.         }  
32.  
33.         public static void ClientListener(object obj)  
34.         {  
35.             TcpClient tcpClient = (TcpClient)obj;  
36.             StreamReader reader = new StreamReader(tcpClient.GetStream());  
37.  
38.             Console.WriteLine("Client connected");  
39.  
40.             while (true)  
41.             {  
42.                 string message = reader.ReadLine();  
43.                 BroadCast(message, tcpClient);  
44.                 Console.WriteLine(message);  
45.             }  
46.         }  
47.  
48.         public static void BroadCast(string msg, TcpClient excludeClient)  
49.         {  
50.             foreach (TcpClient client in tcpClientsList)  
51.             {  
52.                 if (client != excludeClient)  
53.                 {  
54.                     StreamWriter sWriter = new StreamWriter(client.GetStream());  
55.                     sWriter.WriteLine(msg);  
56.                     sWriter.Flush();  
57.                 }  
58.             }  
59.         }  
60.     }  
61. }