C#控制台应用新注册用户登录功能实现问题求助

我开发C#银行控制台应用时，遇到新注册账号无法登录的问题，目前还在完善注册模块的空值/空格错误提示逻辑，代码暂未添加注释，核心诉求是解决用新注册数据实现登录的问题。

问题代码 #

主程序代码

class BankAccount
{
    public static void MainMenu()
    {
        Console.Clear();
        Console.WriteLine("Welcome to Bam's Bank of NSW. \nPlease select from the following menu: \n1: Login \n2: Sign up \n3: Quit");

        int input = Convert.ToInt32(Console.ReadLine());

        switch (input)
        {
            case 1:
                Login();
                break;

            case 2:
                SignUp();
                break;

            case 3:
                Program.Quit();
                break;
        }
    }

    public static void WelcomeMenu()
    {
        Console.Clear();
        Console.WriteLine("Welcome John \nPlease select from the following menu: \n1: View Balance \n2: Deposit \n3: Withdraw \n4: Transfer \n5: Quit");

        int input1 = Convert.ToInt32(Console.ReadLine());

        switch (input1)
        {
            case 1:
                Bank.ViewBalance();
                break;

            case 2:
                Bank.Deposit();
                break;

            case 3:
                Bank.Withdraw();
                break;

            case 4:
                Bank.Transfer();
                break;

            case 5:
                Program.Quit();
                break;
        }
    }

    public static void SignUp()
    {
        Console.Clear();
        Console.WriteLine("Thank you for choosing Bam bank of NSW.\nPlease enter your details to open a new account\n");
        Console.WriteLine("Please enter your name");

        string name = Console.ReadLine();

        Console.WriteLine("Enter your Email. This will become your Username:");

        string email = Console.ReadLine();

        if (email == "")
        {
            Console.WriteLine("Cannot be blank.");
        }

        Console.WriteLine("Please enter your Age:");
        int age = Convert.ToInt32(Console.ReadLine());

        if (age < 18)
        {
            Console.WriteLine("To open an account you need to be 18yrs.");
        }

        Console.WriteLine("Please create a password:");
        string password = Console.ReadLine();

        if (password == "")
        {
            Console.WriteLine("Cannot be blank.");
        }

        Console.WriteLine($"Account successfully created for {email}. Please login");

        Accounts accounts = new Accounts();
        accounts.Name = name;
        accounts.Email = email;
        accounts.Age = age;
        accounts.Password = password;
        Accounts.AllAccounts.Add(accounts);

        Console.ReadKey();
        Login();
    }

    public static void Login()
    {
        Console.Clear();
        Console.WriteLine("Please enter your email/username");

        string uname = Console.ReadLine();
        Accounts accounts = new Accounts();

        if (uname == accounts.Email)
        {
            Console.WriteLine("Please enter your Password");
        }
        else if (uname != accounts.Email)
        {
            TryAgain();
        }

        string pword = Console.ReadLine();

        if (pword == accounts.Password)
        {
            WelcomeMenu();
        }
        else if (pword != accounts.Password)
        {
            TryAgain();
        }
    }

    public static void TryAgain()
    {
        Console.Clear();

        Console.WriteLine("Invalid username/Password. Please select a function.\n1: Try Again \n2: Main Menu \n3: Quit");

        int input2 = Convert.ToInt32(Console.ReadLine());

        switch (input2)
        {
            case 1:
                Login();
                break;

            case 2:
                MainMenu();
                break;

            case 3:
                Program.Quit();
                break;
        }
    }   
}

class Program
{
    static void Main(string[] args)
    {
        BankAccount.MainMenu();
    }

    public static void Quit()
    {
        Console.Clear();
        Console.WriteLine("Thank you and have a nice day! \nPress any key to exit");
        Console.ReadKey();
        return;
    }
}

Accounts类代码

public class Accounts
{
    private static List<Accounts> accounts = new List<Accounts>();

    public static List<Accounts> AllAccounts
    {
        get { return accounts; }
    }
       
    public Accounts()
    {
    }

    public string Name { get; set; }
    public string Email { get; set; }
    public int Age { get; set; }
    public string Password { get; set; }
}       

问题根源 #

登录逻辑的核心错误：Login方法里新建了一个空的Accounts对象，这个对象的Email和Password都是默认的null，根本不会和注册时存入AllAccounts列表里的用户数据匹配，所以永远无法登录成功。

修复后的登录方法 #

替换原来的Login方法，改为从AllAccounts列表中查找匹配邮箱的用户，再验证密码：

public static void Login()
{
    Console.Clear();
    Console.WriteLine("Please enter your email/username");

    string uname = Console.ReadLine();
    // 从已注册账号列表中查找匹配邮箱的用户
    Accounts matchedAccount = Accounts.AllAccounts.FirstOrDefault(a => a.Email == uname);

    if (matchedAccount == null)
    {
        // 没找到对应邮箱的账号，进入重试
        TryAgain();
        return;
    }

    // 找到账号，提示输入密码
    Console.WriteLine("Please enter your Password");
    string pword = Console.ReadLine();

    if (pword == matchedAccount.Password)
    {
        // 登录成功，跳转欢迎菜单（显示当前登录用户的名字）
        Console.Clear();
        Console.WriteLine($"Welcome {matchedAccount.Name} \nPlease select from the following menu: \n1: View Balance \n2: Deposit \n3: Withdraw \n4: Transfer \n5: Quit");
        int input1;
        // 做输入合法性校验，避免非数字输入崩溃
        while (!int.TryParse(Console.ReadLine(), out input1))
        {
            Console.WriteLine("Invalid input, please enter a number.");
        }

        switch (input1)
        {
            case 1:
                Bank.ViewBalance();
                break;

            case 2:
                Bank.Deposit();
                break;

            case 3:
                Bank.Withdraw();
                break;

            case 4:
                Bank.Transfer();
                break;

            case 5:
                Program.Quit();
                break;
        }
    }
    else
    {
        // 密码错误，进入重试
        TryAgain();
    }
}

额外优化建议 #

1. 注册模块错误处理：当前注册时遇到空值/年龄不足的情况，只是输出提示但仍会创建账号，应该添加逻辑阻止无效账号创建，比如：

// 邮箱为空或全空格时，提示并重新进入注册流程
if (string.IsNullOrWhiteSpace(email))
{
    Console.WriteLine("Email cannot be blank or whitespace.");
    Console.ReadKey();
    SignUp();
    return;
}

// 年龄不足18岁时，提示并返回主菜单
if (age < 18)
{
    Console.WriteLine("To open an account you need to be at least 18 years old.");
    Console.ReadKey();
    MainMenu();
    return;
}

2. 输入异常处理：所有使用Convert.ToInt32的地方，建议改用int.TryParse，避免用户输入非数字导致程序崩溃，示例参考修复后登录方法中的输入校验逻辑。

内容的提问来源于stack exchange，提问作者Amy Douglas