c# - 在 .NET Core 3.1 中关闭 C# 套接字的正确方法是什么？
问题描述
问题
我正在尝试处理我的应用程序的断开连接，到目前为止我尝试过的任何方法都失败了，我试图从服务器端断开连接，我试图从客户端断开连接，但两端都收到问题，我在这里想要实现的是通过 QUIT 命令断开应用程序，而不必从关闭图标关闭它，因为它会引发异常
客户端.cs
using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace MessengerConsole
{
class Client
{
static string username;
static int port = 8888;
static IPAddress clientIP;
static Socket serverSocket;
static Thread processThread;
static bool connected = false;
static string GetIp()
{
Console.WriteLine("Type the server ip:");
String clientIP = Console.ReadLine();
Console.WriteLine("Client IP: " + clientIP);
//return clientIP;
//temp solution
return "192.168.0.106";
}
static void printSession()
{
Console.Clear();
Console.WriteLine("//=====================================================");
Console.WriteLine("// Session Details ");
Console.WriteLine("// =====================");
Console.WriteLine("// IP: " + clientIP + "\n// Time: " + DateTime.Now);
Console.WriteLine("//=====================================================");
}
static void clientReceiver()
{
while (true)
{
Thread.Sleep(500);
byte[] buffer = new byte[300];
int rece = serverSocket.Receive(buffer, 0, buffer.Length, 0);
Array.Resize(ref buffer, rece);
if (connected == false)
{
Console.WriteLine("[" + DateTime.Now.ToString() + "] " + Encoding.Default.GetString(buffer) + " Connected!");
connected = true;
}
else
{
if (Encoding.Default.GetString(buffer) == "QUIT")
{
//Quit
Console.WriteLine("Server Shutdown");
serverSocket.Shutdown(SocketShutdown.Both);
serverSocket.Close();
}
else
{
Console.WriteLine("[" + DateTime.Now.ToString() + "] " + Encoding.Default.GetString(buffer));
}
}
}
}
public static void StartClient()
{
processThread = new Thread(clientReceiver);
Console.WriteLine("Please enter your name");
username = Console.ReadLine();
clientIP = IPAddress.Parse(GetIp()); //Returns IP from GetIP()
Console.WriteLine("Please enter HostPort");
//string portString = Console.ReadLine();
//temp port
string portString = "80";
try
{
port = Convert.ToInt32(portString);
}
catch
{
port = 8888;
}
try
{
serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
serverSocket.Connect(new IPEndPoint(clientIP, port));
processThread.Start();
byte[] name = Encoding.Default.GetBytes(username);
//Send Name
serverSocket.Send(name);
// byte[] data = Encoding.Default.GetBytes("<" + username + "> Connected");
//serverSocket.Send(data, 0, data.Length, 0);
printSession();
while (serverSocket.Connected)
{
//byte[] sdata = Encoding.Default.GetBytes("<" + username + ">" + Console.ReadLine());
byte[] sdata = Encoding.Default.GetBytes(Console.ReadLine());
if(Encoding.Default.GetString(sdata) == "QUIT")
{
serverSocket.Send(sdata, sdata.Length, 0);
serverSocket.Shutdown(SocketShutdown.Both);
serverSocket.Disconnect(true);
serverSocket.Close();
}
else
{
serverSocket.Send(sdata, 0, sdata.Length, 0);
}
}
}
catch (Exception e)
{
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine(e.Message);
Console.ForegroundColor = ConsoleColor.White;
}
}
}
}
服务器.cs
using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.Threading;
namespace MessengerConsole
{
class Server
{
//Server Socket
static Socket serverSocket;
//Client Socket
static Socket clientSocket;
//Other Variables
static int port = 8888;
static IPAddress serverIP;
static Thread processThread;
static string username;
static bool connected = false;
//Function returns IP Address
static string GetIp()
{
//Computer Name
string hostname = Dns.GetHostName();
/*The IPHostEntry class associates a Domain Name System (DNS) host name with an array of aliases and
* an array of matching IP addresses.
*/
IPHostEntry ipentry = Dns.GetHostEntry(hostname);
//The Address
IPAddress[] ipAddress = ipentry.AddressList;
return ipAddress[ipAddress.Length - 1].ToString();
}
static void printSession()
{
Console.Clear();
Console.WriteLine("//=====================================================");
Console.WriteLine("// Session Details ");
Console.WriteLine("// =====================");
Console.WriteLine("// You are hosting the server");
Console.WriteLine("// Time: " + DateTime.Now);
Console.WriteLine("//=====================================================");
}
//Receive
static void serverReciever()
{
while (true)
{
Thread.Sleep(500);
byte[] buffer = new byte[300];
int rece = clientSocket.Receive(buffer, 0, buffer.Length, 0);
Array.Resize(ref buffer, rece);
if (connected == false)
{
Console.WriteLine("[" + DateTime.Now.ToString() + "] " + Encoding.Default.GetString(buffer) + " Connected!");
connected = true;
}
else
{
if(Encoding.Default.GetString(buffer) == "QUIT")
{
//Quit
Console.WriteLine("Client disconnected from the chat");
clientSocket.Shutdown(SocketShutdown.Both);
clientSocket.Close();
}
else
{
Console.WriteLine("[" + DateTime.Now.ToString() + "] " + Encoding.Default.GetString(buffer));
}
}
}
}
public static void StartServer()
{
//Thread
processThread = new Thread(serverReciever);
//Display
Console.WriteLine("Your Local Ip is " + GetIp());
Console.WriteLine("Please enter your name");
username = Console.ReadLine();
Console.WriteLine("Please enter HostPort");
// string portString = Console.ReadLine();
//temp solution
string portString = "80";
try
{
port = Convert.ToInt32(portString);
}
catch
{
port = 8888;
}
try
{
//GetIp returns string
serverIP = IPAddress.Parse(GetIp());
//TCP Socket
serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
serverSocket.Bind(new IPEndPoint(serverIP, port));
serverSocket.Listen(0);
//Server Socket listening for client requests
clientSocket = serverSocket.Accept();
printSession();
processThread.Start();
byte[] name = Encoding.Default.GetBytes(username);
clientSocket.Send(name);
while (true)
{
byte[] sdata = Encoding.Default.GetBytes(Console.ReadLine());
clientSocket.Send(sdata, 0, sdata.Length, 0);
}
}
catch
{
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine("Server already open!");
Console.ForegroundColor = ConsoleColor.White;
}
}
}
}
这是我收到的错误
未处理的异常。System.ObjectDisposedException：无法访问已处置的对象。对象名称：“System.Net.Sockets.Socket”。在 System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags, SocketError& errorCode) at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, C:\Users\MessengerConsoleAppV2\MessengerConsole\Client.cs 中 MessengerConsole.Client.clientReceiver() 的 SocketFlags socketFlags)：System.Threading.ThreadHelper.ThreadStart_Context(Object state) 中 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext) 的第 42 行, ContextCallback 回调, 对象状态) --- 从先前抛出异常的位置结束堆栈跟踪 --- 在 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback,
我尝试使用 Socket.Disconnect() 、 Socket.Close() 、 Socket.Dispose() ，它们都产生相同的结果
编辑：
加入return_
if(Encoding.Default.GetString(sdata) == "QUIT")
{
serverSocket.Send(sdata, sdata.Length, 0);
serverSocket.Shutdown(SocketShutdown.Both);
serverSocket.Close();
return;
}
导致服务器端没有错误，但客户端仍然抛出正在访问的已处理对象的异常
未处理的异常。System.ObjectDisposedException：无法访问已处置的对象。对象名称：“System.Net.Sockets.Socket”。在 System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags, SocketError& errorCode) at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, C:\Users\MessengerConsoleAppV2\MessengerConsole\Client.cs 中 MessengerConsole.Client.clientReceiver() 的 SocketFlags socketFlags)：System.Threading.ThreadHelper.ThreadStart_Context(Object state) 中 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext) 的第 44 行, ContextCallback 回调, 对象状态) --- 从先前引发异常的位置结束堆栈跟踪 --- 在 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback,
解决方案
在与QUIT您相关的所有代码位置中，仅关闭和处理套接字，但不从服务该套接字的无限循环返回。Connected我认为在已处置的套接字上评估属性时，会在下一次迭代中抛出此堆栈，return请在关闭套接字后尝试添加语句。
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