Question

c# socket 新手问题。 socket绑定bind()端口后，用Close()关闭后，不能重新开启

程序界面如图：
1.要实现的功能。当勾上 启动监听后，开始监听服务。(ok)
2.取消勾选状态时：关才监听服务。(ok)
3.再次勾选，再次重新开启监听。(这里出错了，显示端口已被绑定)
现在前两个功能都可以。但重新开启时就报错了。

源代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net.Sockets;
using System.Net;
using System.Threading;

namespace 网关
{
public partial class Form1 : Form
{
Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPAddress serverip = Dns.GetHostAddresses("192.168.110.10")[0];

public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
//checkBox1.Checked = true; //启动时自动启动监听
}

private void checkBox1_CheckedChanged(object sender, EventArgs e)
{
if (checkBox1.Checked == true)
{
IPEndPoint serverduankou = new IPEndPoint(serverip, 8000);
server.Bind(serverduankou);
server.Listen(10);
label1.Text = "监听状态:正常";
}
if (checkBox1.Checked == false)
{
//try
//{
// server.Shutdown(SocketShutdown.Both);
// server.Close();

// label1.Text = "监听状态:关闭";
//}
//catch
//{

// //server.Close();
// //label1.Text = "监听状态:关闭";
//}

server.Close();
label1.Text = "监听状态:关闭";
}
}
}
}

Answer 1

用下面代码试试看

 public partial 吵饥class Form1 : Form
   {
        Socket server;
        IPAddress  serverip = Dns.GetHostAddresses("192.168.110.10")[0];    
    
        public Form1()
        {
            InitializeComponent();
        }

        private 码碰郑void Form1_Load(object sender, EventArgs e)
        {
            //checkBox1.Checked = true;  //启动时自动启动监听
        }

        private void checkBox1_CheckedChanged(object sender, EventArgs e)
        {
            if (checkBox1.Checked == true)
            {
                if(CreateSocketAndListen())
                {
                    label1.Text = "监听状态:正常";
                }
                else
                {
                    label1.Text = "Socket发生错误！"; 
                }    
                return;
            }
            else
            {
                if(CloseSocket())
                {
                    label1.Text = "监听状态:关闭";
                }
                else
                {
                    label1.Text = "Socket发生错误！"; 
                }
            }
        }
        
        private bool CreateSocketAndListen()
        {
            try
            {
                server = new Socket(AddressFamily.InterNetwork, 
                     SocketType.Stream, 
                     ProtocolType.Tcp);
                IPEndPoint serverduankou = new IPEndPoint(serverip, 8000);
                server.Bind(serverduankou);
                server.Listen(10);
                return true;
             }
     迟颂        catch
             {   
                 socket = null;
                 return false;
             }
        }
        
        private bool CloseSocket()
        {
             if(socket==null) return false;
             try
             {
                 server.Shutdown(SocketShutdown.Both);
                 server.Close( );
                 server = null;
                 return true;
             }   
             catch
             {
                 server = null;
                 retrun false;
             }
        }
    }
}

追问

直接编译不通过。。提示找不到socket.
我把socket = null;改成server=null;

编译。Socket发生错误！
我追踪了一下。是退出socket时发生错误。。

不知道你那里能不能编译成功。thanks.