一、套接字（socket）概念
套接字（socket）是通信的基石，是支持TCP/IP协议的网络通信的基本操作单元。它是网络通信过程中端点的抽象表示，包含进行网络通信必须的五种信息：连接使用的协议，本地主机的IP地址，本地进程的协议端口，远地主机的IP地址，远地进程的协议端口。
应用层通过传输层进行数据通信时，TCP会遇到同时为多个应用程序进程提供并发服务的问题。多个TCP连接或多个应用程序进程可能需要通过同一个 TCP协议端口传输数据。为了区别不同的应用程序进程和连接，许多计算机操作系统为应用程序与TCP／IP协议交互提供了套接字(Socket)接口。应 用层可以和传输层通过Socket接口，区分来自不同应用程序进程或网络连接的通信，实现数据传输的并发服务。
二、建立socket连接
建立Socket连接至少需要一对套接字，其中一个运行于客户端，称为ClientSocket ，另一个运行于服务器端，称为ServerSocket 。
套接字之间的连接过程分为三个步骤：服务器监听，客户端请求，连接确认。
- 服务器监听：服务器端套接字并不定位具体的客户端套接字，而是处于等待连接的状态，实时监控网络状态，等待客户端的连接请求
- 客户端请求：指客户端的套接字提出连接请求，要连接的目标是服务器端的套接字。为此，客户端的套接字必须首先描述它要连接的服务器的套接字，指出服务器端套接字的地址和端口号，然后就向服务器端套接字提出连接请求。
- 连接确认：当服务器端套接字监听到或者说接收到客户端套接字的连接请求时，就响应客户端套接字的请求，建立一个新的线程，把服务器端套接字的描述发给客户 端，一旦客户端确认了此描述，双方就正式建立连接。而服务器端套接字继续处于监听状态，继续接收其他客户端套接字的连接请求。
三、服务端与客户端代码
服务端前台XMAL
<Window x:Class="Socket通信.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:Socket通信"
mc:Ignorable="d"
Title="服务端" Height="" Width="" Loaded="Window_Loaded" >
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="50*"/>
<RowDefinition Height="190*"/>
<RowDefinition Height="81*"/>
</Grid.RowDefinitions>
<Grid Grid.Row="">
<WrapPanel VerticalAlignment="Center">
<Label Padding="">IP:</Label>
<TextBox Padding="" Width="" Name="IP"></TextBox>
<Label Padding="">Port:</Label>
<TextBox Padding="" Width="" Name="Port"></TextBox>
<Button Padding="" Margin="" Click="Start_View_Click">开始监听</Button>
<Button Padding="" Margin="" Click="Stop_Click">停止监听</Button>
</WrapPanel>
</Grid>
<Grid Grid.Row="">
<ListBox Name="ListConnet"></ListBox>
</Grid>
<Grid Grid.Row="">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="405*"/>
<ColumnDefinition Width="113*"/>
</Grid.ColumnDefinitions> <TextBox Name="SentConnet"></TextBox>
<Button Grid.Column="" Click="Send_Click">发送</Button> </Grid>
</Grid>
</Window>
服务端后台代码
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Windows; namespace Socket通信
{
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
Socket socketSend;
private void Start_View_Click(object sender, RoutedEventArgs e)
{
try
{
//点击开始监听时 在服务端创建一个负责监听IP和端口号的Socket
Socket socketWatch = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPAddress ip = IPAddress.Any; //创建对象端口
IPEndPoint point = new IPEndPoint(ip, Convert.ToInt32(Port.Text));
socketWatch.Bind(point);//绑定端口号
ShowMsg("监听成功!");
socketWatch.Listen();//设置监听
//创建监听线程
Thread thread = new Thread(Listen);
thread.IsBackground = true;
thread.Start(socketWatch);
}
catch { } } void Listen(object o)
{
try
{
Socket socketWatch = o as Socket;
while (true)
{
socketSend = socketWatch.Accept();//等待接收客户端连接
ShowMsg(socketSend.RemoteEndPoint.ToString() + ":" + "连接成功!");
//开启一个新线程，执行接收消息方法
Thread r_thread = new Thread(Received);
r_thread.IsBackground = true;
r_thread.Start(socketSend);
}
}
catch { }
} /// <summary>
/// 服务器端不停的接收客户端发来的消息
/// </summary>
/// <param name="o"></param>
void Received(object o)
{
try
{
Socket socketSend = o as Socket;
while (true)
{
//客户端连接服务器成功后，服务器接收客户端发送的消息
byte[] buffer = new byte[ * * ];
//实际接收到的有效字节数
int len = socketSend.Receive(buffer);
if (len == )
{
break;
}
string str = Encoding.UTF8.GetString(buffer, , len);
ShowMsg("接收到的客户端数据：" + socketSend.RemoteEndPoint + ":" + str);
}
}
catch { }
}
/// <summary>
/// 服务器向客户端发送消息
/// </summary>
/// <param name="str"></param>
void Send(string str)
{
byte[] buffer = Encoding.UTF8.GetBytes(str);
socketSend.Send(buffer);
} void ShowMsg(string msg)
{
Dispatcher.Invoke(() => { ListConnet.Items.Add(msg + "\r\n"); });
} private void Send_Click(object sender, RoutedEventArgs e)
{
Send(SentConnet.Text.Trim());
} private void Window_Loaded(object sender, RoutedEventArgs e)
{
}
private void Stop_Click(object sender, RoutedEventArgs e)
{
socketSend.Close();
ShowMsg("已经停止监听!");
}
}
}
客户端前台XMAL
<Window x:Class="Socket_Client.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:Socket_Client"
mc:Ignorable="d"
Title="客户端" Height="350" Width="525">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="50*"/>
<RowDefinition Height="190*"/>
<RowDefinition Height="81*"/>
</Grid.RowDefinitions>
<Grid Grid.Row="0">
<WrapPanel VerticalAlignment="Center">
<Label Padding="5">IP:</Label>
<TextBox Padding="3" Width="150" Name="IP"></TextBox>
<Label Padding="5">Port:</Label>
<TextBox Padding="3" Width="100" Name="Port"></TextBox>
<Button Padding="3" Margin="3" Click="Start_View_Click">连接</Button>
<Button Padding="3" Margin="3" Click="Stop_Click">断开连接</Button>
</WrapPanel>
</Grid>
<Grid Grid.Row="1">
<TextBox Name="ListConnet"></TextBox>
</Grid>
<Grid Grid.Row="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="405*"/>
<ColumnDefinition Width="113*"/>
</Grid.ColumnDefinitions> <TextBox Name="SentConnet"></TextBox>
<Button Grid.Column="1" Click="Send_Click">发送</Button> </Grid>
</Grid>
</Window>
客户端后台代码
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes; namespace Socket_Client
{
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
Socket socketSend; private void Start_View_Click(object sender, RoutedEventArgs e)
{
try
{
//创建客户端Socket，获得远程ip和端口号
socketSend = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPAddress ip = IPAddress.Parse(IP.Text);
IPEndPoint point = new IPEndPoint(ip, Convert.ToInt32(Port.Text)); socketSend.Connect(point);
ShowMsg("连接成功!");
//开启新的线程，不停的接收服务器发来的消息
Thread c_thread = new Thread(Received);
c_thread.IsBackground = true;
c_thread.Start();
}
catch (Exception)
{
ShowMsg("IP或者端口号错误...");
} }
void ShowMsg(string str)
{ Dispatcher.Invoke(() => { ListConnet.AppendText(str + "\r\n"); });
}
/// <summary>
/// 接收服务端返回的消息
/// </summary>
void Received()
{
while (true)
{
try
{
byte[] buffer = new byte[ * * ];
//实际接收到的有效字节数
int len = socketSend.Receive(buffer);
if (len == )
{
continue;
}
string str = Encoding.UTF8.GetString(buffer, , len);
ShowMsg("接收到的服务端数据：" + socketSend.RemoteEndPoint + ":" + str);
}
catch
{ }
}
} private void Send_Click(object sender, RoutedEventArgs e)
{
try
{
string msg = SentConnet.Text.Trim();
byte[] buffer = new byte[ * * ];
buffer = Encoding.UTF8.GetBytes(msg);
socketSend.Send(buffer);
}
catch { } } private void Stop_Click(object sender, RoutedEventArgs e)
{
socketSend.Close();
ShowMsg("连接已经断开!");
}
}
}
运行结果