如何循环遍历文件来获取数据？

我正在尝试进行基本登录并注册 C# 控制台应用程序，但是，我需要循环遍历我的文件以查看用户输入的用户名和密码在登录时是否匹配。如果用户输入用户名和密码，我希望我的代码遍历我的文件以检查它是否是现有的用户名和密码

这是我的代码：

[Serializable]
public class Users
{
    public string UserName;
    public string Password;

    public Users(string userName, string password)
    {
        UserName = userName;
        Password = password;
    }
}

public class SaveToFile
{
    public static void SerializeSignUpDetails(string userName, string password)
    {
        Users obj = new Users(userName, password);
        IFormatter formatter = new BinaryFormatter();
        Stream stream = new FileStream("SignUp.txt", FileMode.Append, FileAccess.Write);
        formatter.Serialize(stream, obj);
        stream.Close();
    }
    public static Users DeserializeSignUpDetails()
    {
        Stream stream = new FileStream("SignUp.txt", FileMode.Open, FileAccess.Read);
        IFormatter formatter = new BinaryFormatter();
        Users objnew = (Users)formatter.Deserialize(stream);
        stream.Close();
        return objnew;
    }
}

public static void Main(string[] args)
{
    Console.WriteLine("To Login Type 1, To Create a new account Type 2");
    int LogInOrSignUp;
    do
    {
        int.TryParse(Console.ReadLine(), out LogInOrSignUp);
    } while (LogInOrSignUp != 1 && LogInOrSignUp != 2);

    string userName = "";
    string password = "";
    bool successfull = false;
    Users userDetails = SaveToFile.DeserializeSignUpDetails();
    while (!successfull)
    {
        if (LogInOrSignUp == 1)
        {
            Console.WriteLine("Write your username:");
            userName = Console.ReadLine();
            Console.WriteLine("Enter your password:");
            password = Console.ReadLine();
            if (userName == userDetails.UserName && password == userDetails.Password)
            {
                Console.WriteLine("You have logged in successfully!");
                successfull = true;
                break;
            }
            if (!successfull)
            {
                Console.WriteLine("Your username or password is incorect, try again!");
            }
        }

        else if (LogInOrSignUp == 2)
        {
            Console.WriteLine("Enter a username:");
            userName = Console.ReadLine();

            Console.WriteLine("Enter a password:");
            password = Console.ReadLine();

            successfull = true;
            SaveToFile.SerializeSignUpDetails(userName, password);
        }
    }
}

我想使用 foreach 循环遍历我的文件，但我不知道如何操作。

任何帮助表示赞赏！

要使用序列化保留多个条目的登录记录，您需要序列化对象列表。在您的情况下，您可以创建几个可序列化的类，User封装单个条目的数据的类，以及Users包含一个类List<User>对象加上数据操作方法。

^{✔ Note: Name as you prefer.}

◉ 要导入的命名空间

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;

◉ The User class

[Serializable]
public class User
{
    public string UserName { get; set; }
    public string Password { get; set; }
    //More details...

    public User(string userName, string password)
    {
        UserName = userName;
        Password = password;
    }

    public override string ToString() => $"{UserName}, {Password}";
}

◉ The Users class

[Serializable]
public class Users
{
    public readonly List<User> Accounts;

    public Users() => Accounts = new List<User>();

    public void Save(string filePath)
    {
        if (string.IsNullOrEmpty(filePath)) return;

        var bf = new BinaryFormatter();
        using (var fs = new FileStream(filePath, FileMode.Create))
            bf.Serialize(fs, this);
    }

    public static Users Load(string filePath)
    {
        if (!File.Exists(filePath)) return null;

        var bf = new BinaryFormatter();
        using (var sr = new FileStream(filePath, FileMode.Open))
            return bf.Deserialize(sr) as Users;
    }

    public bool ContainsUserName(string userName) => 
        Accounts.Any(x => x.UserName == userName);

    public bool ContainsAccount(string userName, string pass) =>
        Accounts.Any(x => x.UserName == userName && x.Password == pass);

    public User Get(string userName, string pass) =>
        Accounts.FirstOrDefault(x => x.UserName == userName && x.Password == pass);

    public bool Add(string userName, string pass)
    {
        if (ContainsUserName(userName)) return false;

        Accounts.Add(new User(userName, pass));
        return true;
    }
}

在您的实现中，创建、加载和保存数据：

//Load...
users = Users.Load(dataFilePath);

//Or create new object...
if (users is null)
    users = new Users();

//and when it comes to save...
users.Save(dataFilePath);

Use the ContainsUserName方法来查明给定的用户名是否已经存在，这样就可以避免重复。这Add方法将执行相同的操作，并且会将有效的新条目添加到列表中。这Get方法在列表中搜索给定的用户名和密码并返回User如有其他情况则反对null，以及ContainsAccount如果您不需要返回，方法将执行相同的操作User object.

var user = users.Get("user", "pass");
if (user is null)
    Console.WriteLine("Incorrect username and/or password...");

//or
if (!users.ContainsAccount("user", "pass"))
    Console.WriteLine("Incorrect username and/or password...");

将其应用到你的main:

public static void Main(string[] args)
{
    Console.WriteLine("To Login Type 1, To Create a new account Type 2");
    int LogInOrSignUp;
    do
    {
        int.TryParse(Console.ReadLine(), out LogInOrSignUp);
    } while (LogInOrSignUp != 1 && LogInOrSignUp != 2);

    var filePath = Path.Combine(AppContext.BaseDirectory, "SignUp.dat");
    var userName = "";
    var password = "";
    var successfull = false;
    var userDetails = Users.Load(filePath);

    if (userDetails is null)
        userDetails = new Users();

    while (!successfull)
    {
        if (LogInOrSignUp == 1)
        {
            Console.WriteLine("Write your username:");
            userName = Console.ReadLine();
            Console.WriteLine("Enter your password:");
            password = Console.ReadLine();
            if (userDetails.ContainsAccount(userName, password))
            {
                Console.WriteLine("You have logged in successfully!");
                successfull = true;
                break;
            }
            else
                Console.WriteLine("Your username or password is incorect, try again!");
        }

        else //if (LogInOrSignUp == 2)
        {
            Console.WriteLine("Enter a username:");
            userName = Console.ReadLine();

            if (userDetails.ContainsUserName(userName))
                Console.WriteLine("The username is taken. Try another one.");
            else
            {
                Console.WriteLine("Enter a password:");
                password = Console.ReadLine();

                successfull = true;
                userDetails.Add(userName, password);
                userDetails.Save(filePath);
                Console.WriteLine($"A new account for {userName} has been created.");
            }
        }
    }
    Console.ReadLine();
}

^{✔ Note: Better to use the switch https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/switch statement to select LogInOrSignUp instead of the if statements}