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c# - 更改字典中的值不保存在循环方法中

问题描述

我正在创建 2 个字符串，然后将其存储在字典中。看来程序没有保存字符串的值。

我猜这是在我doRequest反复调用时发生的，因为我正在创建存储在字典中的变量，doRequest它只是重新创建它们。我尝试在外部声明变量，doRequest但这似乎并没有解决我遇到的问题。

我是在正确的轨道上声明方法之外的变量并做错了，还是有更好的方法来存储变量？

public class Respond
{
    static void Main(string[] args)
    {
        RunServer();
    }

    //public static string user = null;
    //public static string location = null;
    static void RunServer()
    {
        TcpListener listener;
        Socket connection;
        NetworkStream socketStream;
        try
        {
            listener = new TcpListener(IPAddress.Any, 43);
            listener.Start();
            Console.WriteLine("server is listening");
            while (true)
        {
            connection = listener.AcceptSocket();
            socketStream = new NetworkStream(connection);
            Console.WriteLine("connection received");
            DoRequest(socketStream);
            socketStream.Close();
            connection.Close();
        }
        catch (Exception e)
        {
            Console.WriteLine("Exception: " + e.ToString());
        }
    }

    static void DoRequest(NetworkStream socketStream)
    {
        Hashtable userPlusLocation = new Hashtable();
        Dictionary<string, string> userPlusLocation2 = new Dictionary<string, string>();

        //string user = null;
        //string location = null;
        //userPlusLocation.Add(user, location); //user = key , location = value

        StreamWriter sw = new StreamWriter(socketStream);
        StreamReader sr = new StreamReader(socketStream);

        string line = sr.ReadLine().Trim();
        Console.WriteLine("respond received: " + line);
        string[] sections = line.Split(new char[] { ' ' }, 2);

        try
        {
            //write if statements for user and location inputs
            if (user == null)
            {
                user = sections[0];
                userPlusLocation2.Add(user, location);
            }

            if (sections.Length == 1)
            {
                sw.WriteLine(userPlusLocation2[user]);
                sw.Flush();
                Console.WriteLine("single arg received");
                Console.WriteLine("location: " + userPlusLocation2[user]);
            }
            else
            {
                location = sections[1];
                userPlusLocation2[user] = location;
                sw.WriteLine("OK");
                sw.Flush();
                Console.WriteLine("location: " + userPlusLocation2[user]);
            }
        }
        catch(Exception e)
        {
            sw.WriteLine("error stuff: " + e);
        }
    }
}

标签： c#stringdictionary

解决方案

如果您想保留 hastable 和字典值，您还需要在 doRequest 方法之外声明它们。

    Hashtable userPlusLocation = new Hashtable();
    Dictionary<string, string> userPlusLocation2 = new Dictionary<string, string>();

    //string user = null;
    //string location = null;
    //userPlusLocation.Add(user, location); //user = key , location = value

doRequest 中的上述代码块创建了仅对 doRequest 方法本地的变量，因此一旦方法完成，变量也是如此。要解决此问题，请在方法之外声明您需要的所有内容。并注意不要重新声明它

= new stufff

在你完成之前，因为这会覆盖你的值。

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