Socket 类

项目
08/17/2007

实现 Berkeley 套接字接口。

**命名空间:**System.Net.Sockets
**程序集:**System（在 system.dll 中）

语法

声明
Public Class Socket
    Implements IDisposable
用法
Dim instance As Socket

public class Socket : IDisposable

public ref class Socket : IDisposable

public class Socket implements IDisposable

public class Socket implements IDisposable

备注

Socket 类为网络通信提供了一套丰富的方法和属性。Socket 类允许您使用 ProtocolType 枚举中所列出的任何一种协议执行异步和同步数据传输。Socket 类遵循异步方法的 .NET Framework 命名模式；例如，同步 Receive 方法对应于异步 BeginReceive 和 EndReceive 方法。

如果应用程序在执行期间只需要一个线程，请使用下面的方法，这些方法适用于同步操作模式。

如果当前使用的是面向连接的协议（如 TCP），则服务器可以使用 Listen 方法侦听连接。Accept 方法处理任何传入的连接请求，并返回可用于与远程主机进行数据通信的 Socket。可以使用此返回的 Socket 来调用 Send 或 Receive 方法。如果要指定本地 IP 地址和端口号，请在调用 Listen 方法之前先调用 Bind 方法。如果您希望基础服务提供程序为您分配可用端口，请使用端口号 0。如果希望连接到侦听主机，请调用 Connect 方法。若要进行数据通信，请调用 Send 或 Receive 方法。
如果当前使用的是无连接协议（如 UDP），则根本不需要侦听连接。调用 ReceiveFrom 方法可接受任何传入的数据报。使用 SendTo 方法可将数据报发送到远程主机。

若要在执行过程中使用单独的线程处理通信，请使用下面的方法，这些方法适用于异步操作模式。

如果当前使用的是面向连接的协议（如 TCP），则可使用 Socket、BeginConnect 和 EndConnect 方法来连接侦听主机。通过使用 BeginSend 和 EndSend 方法，或者使用 BeginReceive 和 EndReceive 方法，可以进行异步数据通信。可以使用 BeginAccept 和 EndAccept 处理传入的连接请求。
如果您使用的是 UDP 等无连接协议，则可以使用 BeginSendTo 和 EndSendTo 来发送数据报，而使用 BeginReceiveFrom 和 EndReceiveFrom 来接收数据报。

如果对一个套接字执行多个异步操作，它们不一定按启动时的顺序完成。

当数据发送和数据接收完成之后，可使用 Shutdown 方法来禁用 Socket。在调用 Shutdown 之后，可调用 Close 方法来释放与 Socket 关联的所有资源。

通过 Socket 类，您可以使用 SetSocketOption 方法来配置 Socket。可以使用 GetSocketOption 方法来检索这些设置。

提示

如果要编写相对简单的应用程序，而且不需要最高的性能，则可以考虑使用 TcpClient、TcpListener 和 UdpClient。这些类为 Socket 通信提供了更简单、对用户更友好的接口。

Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows CE 平台说明： 并非所有设备的操作系统会支持全部的套接字选项。

示例

下面的代码示例演示如何使用 Socket 类向 HTTP 服务器发送数据和接收响应。接收到整个页前，此示例将一直处于阻止状态。

Imports System
Imports System.Text
Imports System.IO
Imports System.Net
Imports System.Net.Sockets
Imports Microsoft.VisualBasic

Public Class GetSocket
   
   Private Shared Function ConnectSocket(server As String, port As Integer) As Socket
      Dim s As Socket = Nothing
      Dim hostEntry As IPHostEntry = Nothing      
     
         ' Get host related information.
        hostEntry = Dns.GetHostEntry(server)
         
         ' Loop through the AddressList to obtain the supported AddressFamily. This is to avoid
         ' an exception that occurs when the host host IP Address is not compatible with the address family
         ' (typical in the IPv6 case).
      Dim address As IPAddress
 
        For Each address In  hostEntry.AddressList
            Dim endPoint As New IPEndPoint(address, port)
            Dim tempSocket As New Socket(endPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp)
      
            tempSocket.Connect(endPoint)
            
            If tempSocket.Connected Then
               s = tempSocket
               Exit For
            End If

         Next address
      
      Return s
   End Function 
   
   
   ' This method requests the home page content for the specified server.
   
   Private Shared Function SocketSendReceive(server As String, port As Integer) As String
      'Set up variables and String to write to the server.
      Dim ascii As Encoding = Encoding.ASCII
      Dim request As String = "GET / HTTP/1.1" + ControlChars.Cr + ControlChars.Lf + "Host: " + server + ControlChars.Cr + ControlChars.Lf + "Connection: Close" + ControlChars.Cr + ControlChars.Lf + ControlChars.Cr + ControlChars.Lf
      Dim bytesSent As [Byte]() = ascii.GetBytes(request)
      Dim bytesReceived(255) As [Byte]
      
      ' Create a socket connection with the specified server and port.
      Dim s As Socket = ConnectSocket(server, port)
      
      If s Is Nothing Then
         Return "Connection failed"
      End If 
      ' Send request to the server.
      s.Send(bytesSent, bytesSent.Length, 0)
      
      ' Receive the server  home page content.
      Dim bytes As Int32
      
      ' Read the first 256 bytes.
      Dim page as [String] = "Default HTML page on " + server + ":" + ControlChars.Cr + ControlChars.Lf
      
      ' The following will block until the page is transmitted.
      Do
         bytes = s.Receive(bytesReceived, bytesReceived.Length, 0)
            page = page + Encoding.ASCII.GetString(bytesReceived, 0, bytes)
      Loop While bytes > 0
      
      Return page
   End Function 
   
   'Entry point which delegates to C-style main Private Function
   Public Overloads Shared Sub Main()
      Main(System.Environment.GetCommandLineArgs())
   End Sub
   
   
   Overloads Private Shared Sub Main(args() As String)
      Dim host As String
      Dim port As Integer = 80
      
      If args.Length = 1 Then
         ' If no server name is passed as argument to this program, 
         ' use the current host name as default.
         host = Dns.GetHostName()
      Else
         host = args(1)
      End If 
      
      Dim result As String = SocketSendReceive(host, port)
      
      Console.WriteLine(result)
   End Sub 'Main
End Class

using System;
using System.Text;
using System.IO;
using System.Net;
using System.Net.Sockets;

public class GetSocket
{
    private static Socket ConnectSocket(string server, int port)
    {
        Socket s = null;
        IPHostEntry hostEntry = null;
        
        // Get host related information.
        hostEntry = Dns.GetHostEntry(server);

        // Loop through the AddressList to obtain the supported AddressFamily. This is to avoid
        // an exception that occurs when the host IP Address is not compatible with the address family
        // (typical in the IPv6 case).
        foreach(IPAddress address in hostEntry.AddressList)
        {
            IPEndPoint ipe = new IPEndPoint(address, port);
            Socket tempSocket = 
                new Socket(ipe.AddressFamily, SocketType.Stream, ProtocolType.Tcp);

            tempSocket.Connect(ipe);

            if(tempSocket.Connected)
            {
                s = tempSocket;
                break;
            }
            else
            {
                continue;
            }
        }
        return s;
    }

    // This method requests the home page content for the specified server.
    private static string SocketSendReceive(string server, int port) 
    {
        string request = "GET / HTTP/1.1\r\nHost: " + server + 
            "\r\nConnection: Close\r\n\r\n";
        Byte[] bytesSent = Encoding.ASCII.GetBytes(request);
        Byte[] bytesReceived = new Byte[256];
       
        // Create a socket connection with the specified server and port.
        Socket s = ConnectSocket(server, port);

        if (s == null)
            return ("Connection failed");
      
        // Send request to the server.
        s.Send(bytesSent, bytesSent.Length, 0);  
        
        // Receive the server home page content.
        int bytes = 0;
        string page = "Default HTML page on " + server + ":\r\n";

        // The following will block until te page is transmitted.
        do {
            bytes = s.Receive(bytesReceived, bytesReceived.Length, 0);
            page = page + Encoding.ASCII.GetString(bytesReceived, 0, bytes);
        }
        while (bytes > 0);
        
        return page;
    }
    
    public static void Main(string[] args) 
    {
        string host;
        int port = 80;

        if (args.Length == 0)
            // If no server name is passed as argument to this program, 
            // use the current host name as the default.
            host = Dns.GetHostName();
        else
            host = args[0];

        string result = SocketSendReceive(host, port); 
        Console.WriteLine(result);
    }
}

#using <System.dll>

using namespace System;
using namespace System::Text;
using namespace System::IO;
using namespace System::Net;
using namespace System::Net::Sockets;
using namespace System::Collections;
Socket^ ConnectSocket( String^ server, int port )
{
   Socket^ s = nullptr;
   IPHostEntry^ hostEntry = nullptr;
   
   // Get host related information.
   hostEntry = Dns::Resolve( server );
   
   // Loop through the AddressList to obtain the supported AddressFamily. This is to avoid
   // an exception that occurs when the host IP Address is not compatible with the address family
   // (typical in the IPv6 case).
   IEnumerator^ myEnum = hostEntry->AddressList->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      IPAddress^ address = safe_cast<IPAddress^>(myEnum->Current);
      IPEndPoint^ endPoint = gcnew IPEndPoint( address,port );
      Socket^ tmpS = gcnew Socket( endPoint->AddressFamily,SocketType::Stream,ProtocolType::Tcp );
      tmpS->Connect( endPoint );
      if ( tmpS->Connected )
      {
         s = tmpS;
         break;
      }
      else
      {
         continue;
      }
   }

   return s;
}


// This method requests the home page content for the specified server.
String^ SocketSendReceive( String^ server, int port )
{
   String^ request = String::Concat( "GET / HTTP/1.1\r\nHost: ", server, "\r\nConnection: Close\r\n\r\n" );
   array<Byte>^bytesSent = Encoding::ASCII->GetBytes( request );
   array<Byte>^bytesReceived = gcnew array<Byte>(256);
   
   // Create a socket connection with the specified server and port.
   Socket^ s = ConnectSocket( server, port );
   if ( s == nullptr )
      return ("Connection failed");

   
   // Send request to the server.
   s->Send( bytesSent, bytesSent->Length, static_cast<SocketFlags>(0) );
   
   // Receive the server home page content.
   int bytes = 0;
   String^ strRetPage = String::Concat( "Default HTML page on ", server, ":\r\n" );
   do
   {
      bytes = s->Receive( bytesReceived, bytesReceived->Length, static_cast<SocketFlags>(0) );
      strRetPage = String::Concat( strRetPage, Encoding::ASCII->GetString( bytesReceived, 0, bytes ) );
   }
   while ( bytes > 0 );

   return strRetPage;
}

int main()
{
   array<String^>^args = Environment::GetCommandLineArgs();
   String^ host;
   int port = 80;
   if ( args->Length == 1 )
      
   // If no server name is passed as argument to this program, 
   // use the current host name as default.
   host = Dns::GetHostName();
   else
      host = args[ 1 ];

   String^ result = SocketSendReceive( host, port );
   Console::WriteLine( result );
}

import System.*;
import System.Text.*;
import System.IO.*;
import System.Net.*;
import System.Net.Sockets.*;

public class GetSocket
{
    private static Socket ConnectSocket(String server, int port)
    {
        Socket s = null;
        IPHostEntry hostEntry = null;

        // Get host related information.
        hostEntry = Dns.Resolve(server);

        // Loop through the AddressList to obtain the supported AddressFamily. 
        // This is to avoid an exception that occurs when the host IP Address 
        // is not compatible with the address family
        // (typical in the IPv6 case).
        for (int iCtr = 0; iCtr < hostEntry.get_AddressList().length; iCtr++) {
            IPAddress address = hostEntry.get_AddressList()[iCtr];
            IPEndPoint ipe = new IPEndPoint(address, port);
            Socket tempSocket = new Socket(ipe.get_AddressFamily(),
                SocketType.Stream, ProtocolType.Tcp);
            tempSocket.Connect(ipe);
            if (tempSocket.get_Connected()) {
                s = tempSocket;
                break;
            }
            else {
                continue;
            }
        }

        return s;
    } //ConnectSocket

    // This method requests the home page content for the specified server.
    private static String SocketSendReceive(String server, int port)
    {
        String request = "GET / HTTP/1.1\r\nHost: " + server 
            + "\r\nConnection: Close\r\n\r\n";
        System.Byte bytesSent[] = 
            (System.Byte[])Encoding.get_ASCII().GetBytes(request);
        System.Byte bytesReceived[] = new System.Byte[256];

        // Create a socket connection with the specified server and port.
        Socket s = ConnectSocket(server, port);
        if (s == null) {
            return "Connection failed";
        }

        // Send request to the server.
        s.Send((ubyte[])bytesSent, bytesSent.length, (SocketFlags)0);

        // Receive the server home page content.
        int bytes = 0;
        String page = "Default HTML page on " + server + ":\r\n";

        // The following will block until te page is transmitted.
        do {
            bytes = s.Receive((ubyte[])bytesReceived,
                bytesReceived.length, (SocketFlags)0);
            page = page + Encoding.get_ASCII().GetString(
                (ubyte[])bytesReceived, 0, bytes);
        } while (bytes > 0);
        return page;
    } //SocketSendReceive

    public static void main(String[] args)
    {
        String host;
        int port = 80;
        if (args.length == 0) {
            // If no server name is passed as argument to this program, 
            // use the current host name as the default.
            host = Dns.GetHostName();
        }
        else {
            host = args[0];
        }
        String result = SocketSendReceive(host, port);
        Console.WriteLine(result);
    } //main
} //GetSocket

.NET Framework 安全性

SocketPermission 建立外向连接或接受传入请求。

继承层次结构

System.Object
System.Net.Sockets.Socket

线程安全

此类的实例是线程安全的。

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

通过

Socket 类

语法

备注

示例

.NET Framework 安全性

继承层次结构

线程安全

平台

版本信息

.NET Framework

.NET Compact Framework

请参见

参考

其他资源