form1.cs

wintalk 聊天程序是学习csharp网络编程的好材料

using System;
using System.IO;
using System.Text;
using System.Threading;
using System.Net;
using System.Net.Sockets;
using System.Drawing;
using System.Windows.Forms;

class App
{        
	// Entry point
	public static void Main(String[] args)
	{        
		// If the args parse in known way then run the app
		if(ParseArgs(args))
		{           
			// Create a custom Talker object
			Talker talker = new Talker(endPoint, client);
			// Pass the object reference to a new form object
			TalkForm form = new TalkForm(talker);                   
			// Start the talker "talking"
			talker.Start();

			// Run the applications message pump
			Application.Run(form);
		}        
	}

	// Parsed Argument Storage
	private static IPEndPoint endPoint;
	private static bool client;

	// Parse command line arguments
	private static bool ParseArgs(String[] args)
	{
		try
		{        
			if(args.Length == 0)
			{
				client = false;
				endPoint = new IPEndPoint(IPAddress.Any,5150);
				return true;
			}

			switch(Char.ToUpper(args[0][1]))
			{
				case 'L':
					int port = 5150;
					if(args.Length > 1)
					{
						port = Convert.ToInt32(args[1]);    
					}
					endPoint = new IPEndPoint(IPAddress.Any,port);
					client = false;
					break;
				case 'C':
					port = 5150;
					String address = "127.0.0.1";
					client = true;
					if(args.Length > 1)
					{
						address = args[1];
						port = Convert.ToInt32(args[2]);                                        
					}                
					endPoint = new IPEndPoint(Dns.Resolve(address).AddressList[0], port);
					break;
				default:
					ShowUsage();
					return false;
			}
		}
		catch
		{
			ShowUsage();
			return false;
		}    
    
		return true;
	}

	// Show sample usage
	private static void ShowUsage()
	{
		MessageBox.Show("WinTalk [switch] [parameters...]\n\n"+
			"  /L  [port]\t\t-- Listens on a port.  Default:  5150\n"+
			"  /C  [address] [port]\t-- Connects to an address and port.\n\n"+
			"Example Server - \n"+
			"Wintalk /L\n\n"+
			"Example Client - \n"+
			"Wintalk /C ServerMachine 5150","WinTalk Usage");
	}
}

// UI class for the sample
class TalkForm:Form 
{    
	public TalkForm(Talker talker) 
	{
		// Associate for method with the talker object
		this.talker = talker;
		talker.Notifications += new 
			Talker.NotificationCallback(HandleTalkerNotifications);

		// Create a UI elements
		Splitter talkSplitter = new Splitter();
		Panel talkPanel = new Panel();        

		receiveText = new TextBox();
		sendText = new TextBox(); 
        
		// we'll support up to 64k data in our text box controls
		receiveText.MaxLength = sendText.MaxLength = 65536;
		statusText = new Label();
     
		// Initialize UI elements
		receiveText.Dock = DockStyle.Top;
		receiveText.Multiline = true;
		receiveText.ScrollBars = ScrollBars.Both;
		receiveText.Size = new Size(506, 192);
		receiveText.TabIndex = 1;
		receiveText.Text = "";
		receiveText.WordWrap = false;
		receiveText.ReadOnly = true;
        
		talkPanel.Anchor = (AnchorStyles.Top|AnchorStyles.Bottom
			|AnchorStyles.Left|AnchorStyles.Right);
		talkPanel.Controls.AddRange(new Control[] {sendText,
													  talkSplitter,
													  receiveText});
		talkPanel.Size = new Size(506, 371);
		talkPanel.TabIndex = 0;

		talkSplitter.Dock = DockStyle.Top;
		talkSplitter.Location = new Point(0, 192);
		talkSplitter.Size = new Size(506, 6);
		talkSplitter.TabIndex = 2;
		talkSplitter.TabStop = false;
        
		statusText.Dock = DockStyle.Bottom;
		statusText.Location = new Point(0, 377);
		statusText.Size = new Size(507, 15);
		statusText.TabIndex = 1;
		statusText.Text = "Status:";

		sendText.Dock = DockStyle.Fill;
		sendText.Location = new Point(0, 198);
		sendText.Multiline = true;
		sendText.ScrollBars = ScrollBars.Both;
		sendText.Size = new Size(506, 173);
		sendText.TabIndex = 0;
		sendText.Text = "";
		sendText.WordWrap = false;
		sendText.TextChanged += new EventHandler(HandleTextChange);
		sendText.Enabled = false;

		AutoScaleBaseSize = new Size(5, 13);
		ClientSize = new Size(507, 392);
		Controls.AddRange(new Control[] {statusText,
											talkPanel});
		Text = "WinTalk";

		this.ActiveControl = sendText;     
	}    

	// When the app closes, dispose of the talker object
	protected override void OnClosed(EventArgs e)
	{
		if(talker!=null)
		{
			// remove our notification handler
			talker.Notifications -= new 
				Talker.NotificationCallback(HandleTalkerNotifications);
            
			talker.Dispose();
		}
		base.OnClosed(e);
	}
    
	// Handle notifications from the talker object
	private void HandleTalkerNotifications(
		Talker.Notification notify, Object data)
	{
		switch(notify)
		{
			case Talker.Notification.Initialized:
				break;
				// Respond to status changes
			case Talker.Notification.StatusChange:
				Talker.Status status = (Talker.Status)data;
				statusText.Text = String.Format("Status: {0}", status);
				if(status == Talker.Status.Connected)
				{
					sendText.Enabled = true;
				}
				break;
				// Respond to received text
			case Talker.Notification.Received:
				receiveText.Text = data.ToString();
				receiveText.SelectionStart = Int32.MaxValue;
				receiveText.ScrollToCaret();        
				break;
				// Respond to error notifications
			case Talker.Notification.Error:            
				Close(data.ToString());        
				break;
				// Respond to end
			case Talker.Notification.End:                                    
				MessageBox.Show(data.ToString(), "Closing WinTalk");             
				Close();
				break;
			default:
				Close();
				break;
		}
	}

	// Handle text change notifications and send talk
	private void HandleTextChange(Object sender, EventArgs e)
	{
		if(talker != null)
		{
			talker.SendTalk((sender as TextBox).Text);
		}        
	}   

	// Close with an explanation
	private void Close(String message)
	{   
		MessageBox.Show(message, "Error!");        
		Close();
	}

	// Private UI elements
	private TextBox receiveText;        
	private TextBox sendText;    
	private Label statusText;
	private Talker talker;   
}

// An encapsulation of the Sockets class used for socket chatting
class Talker:IDisposable
{
	// Construct a talker 
	public Talker(IPEndPoint endPoint, bool client)
	{
		this.endPoint = endPoint;
		this.client = client;

		socket = null;
		reader = null;
		writer = null;

		statusText = prevSendText = prevReceiveText = String.Empty;
	}

	// Finalize a talker
	~Talker()
	{
		Dispose();
	}

	// Dispose of resources and surpress finalization
	public void Dispose()
	{        
		GC.SuppressFinalize(this);
		if(reader != null)
		{
			reader.Close();
			reader = null;
		}
		if(writer != null)
		{
			writer.Close();
			writer = null;
		}
		if(socket != null)
		{
			socket.Close();
			socket = null;
		}        
	}

	// Nested delegat class and matchine event
	public delegate 
		void NotificationCallback(Notification notify, Object data);
	public event NotificationCallback Notifications;

	// Nested enum for notifications
	public enum Notification
	{
		Initialized = 1,
		StatusChange,
		Received,
		End,
		Error
	}

	// Nested enum for supported states
	public enum Status
	{
		Listening,
		Connected
	}

	// Start up the talker's functionality
	public void Start()
	{
		ThreadPool.QueueUserWorkItem(new WaitCallback(EstablishSocket));
	}

	// Send text to remote connection
	public void SendTalk(String newText)
	{                
		String send;
		// Is this an append
		if((prevSendText.Length <= newText.Length) && String.CompareOrdinal(
			newText, 0, prevSendText, 0, prevSendText.Length)==0)
		{
			String append = newText.Substring(prevSendText.Length);
			send = String.Format("A{0}:{1}", append.Length, append);
			// or a complete replacement
		}
		else
		{
			send = String.Format("R{0}:{1}", newText.Length, newText);
		}   
		// Send the data and flush it out
		writer.Write(send);
		writer.Flush();
		// Save the text for future comparison
		prevSendText = newText;
	}

	// Send a status notification
	private void SetStatus(Status status)
	{
		this.status = status;
		Notifications(Notification.StatusChange, status);
	}

	// Establish a socket connection and start receiving
	private void EstablishSocket(Object state)
	{               
		try
		{
			// If not client, setup listner
			if(!client)
			{
				Socket listener;
                
				try
				{
					listener = new Socket(AddressFamily.InterNetwork,
						SocketType.Stream, ProtocolType.Tcp);
					listener.Blocking = true;
					listener.Bind(endPoint);
					SetStatus(Status.Listening);                    
					listener.Listen(0);
					socket = listener.Accept();
					listener.Close();                                
				}
				catch(SocketException e)
				{
					// If there is already a listener on this port try client
					if(e.ErrorCode == 10048)
					{
						client = true;
						endPoint = new IPEndPoint(
							Dns.Resolve("127.0.0.1").AddressList[0], endPoint.Port);
					}
					else
					{
						Notifications(
							Notification.Error, 
							"Error Initializing Socket:\n"+e.ToString());                        
					}
				}                                    
			}

			// Try a client connection
			if(client)
			{
				Socket temp = new 
					Socket(AddressFamily.InterNetwork,
					SocketType.Stream,ProtocolType.Tcp);
				temp.Blocking = true;
				temp.Connect(endPoint);
				socket = temp;
			}

			// If it all worked out, create stream objects
			if(socket != null)
			{
				SetStatus(Status.Connected);                 
				NetworkStream stream = new NetworkStream(socket);
				reader = new StreamReader(stream);
				writer = new StreamWriter(stream);
				Notifications(Notification.Initialized, this);                
			}
			else
			{
				Notifications(Notification.Error, 
					"Failed to Establish Socket");
			}

			// Start receiving talk
			// Note: on w2k and later platforms, the NetworkStream.Read()
			// method called in ReceiveTalk will generate an exception when
			// the remote connection closes. We handle this case in our
			// catch block below.
			ReceiveTalk();

			// On Win9x platforms, NetworkStream.Read() returns 0 when
			// the remote connection closes, prompting a graceful return
			// from ReceiveTalk() above. We will generate a Notification.End
			// message here to handle the case and shut down the remaining
			// WinTalk instance.
			Notifications(Notification.End, "Remote connection has closed.");
            
		}
		catch(IOException e)
		{ 
			SocketException sockExcept = e.InnerException as SocketException; 
			if(sockExcept != null && 10054 == sockExcept.ErrorCode)
			{
				Notifications(Notification.End, "Remote connection has closed.");
			}
			else
			{
				if (Notifications != null)
					Notifications(Notification.Error, "Socket Error:\n"+e.Message);
			}                
		}
		catch(Exception e)
		{              
			Notifications(Notification.Error, "Socket Error:\n"+e.Message);
		}
	}

	// Receive chat from remote client
	private void ReceiveTalk()
	{
		char[] commandBuffer = new char[20];
		char[] oneBuffer = new char[1];
		int readMode = 1;
		int counter = 0;        
		StringBuilder text = new StringBuilder();

		while(readMode != 0)
		{
			if(reader.Read(oneBuffer, 0, 1)==0)
			{
				readMode = 0;
				continue;
			}

			switch(readMode)
			{
				case 1:        
					if(counter == commandBuffer.Length)
					{
						readMode = 0;
						continue;
					}
					if(oneBuffer[0] != ':')
					{
						commandBuffer[counter++] = oneBuffer[0];
					}
					else
					{
						counter = Convert.ToInt32(
							new String(commandBuffer, 1, counter-1));
						if(counter>0)
						{
							readMode = 2;                            
							text.Length = 0;
						}
						else if(commandBuffer[0] == 'R')
						{
							counter = 0;
							prevReceiveText = String.Empty;
							Notifications(Notification.Received, prevReceiveText);
						}
					}
					break;
				case 2:
					text.Append(oneBuffer[0]);
					if(--counter == 0)
					{
						switch(commandBuffer[0])
						{
							case 'R':
								prevReceiveText = text.ToString();
								break;
							default:
								prevReceiveText += text.ToString();
								break;
						}                    
						readMode = 1;

						Notifications(Notification.Received, prevReceiveText);                    
					}
					break;
				default:
					readMode = 0;
					continue;
			}            
		}        
	}

	private Socket socket;

	private TextReader reader;
	private TextWriter writer;
    
	bool client;
	IPEndPoint endPoint;

	private String prevSendText;
	private String prevReceiveText;
	private String statusText;

	private Status status;    
}