将用户输入添加到现有列表中

Question

I'm creating a .NET core app where the user can add, edit, delete or view players and some stats. I've got an abstract Players Class with children(HockeyPlayers, BasketBall players etc)

In my Main class I have created a List and populated it with some default players.

List<Player> players = new List<Player>()
          {
              new HockeyPlayer
              {
                  PlayerId = 1,
                  PlayerName = "Mitch marner",
                  TeamName = "Toronto Maple Leafs",
                  GamesPlayed = 5,
                  Assists = 12,
                  Goals = 7
              },
              new HockeyPlayer
              {
                  PlayerId = 2,
                  PlayerName = "Nazem kadri",
                  TeamName = "Colorado Avalanche",
                  GamesPlayed = 12,
                  Assists = 11,
                  Goals = 8
              },
              new BasketballPlayer
              {
                  PlayerId = 3,
                  PlayerName = "Stephen Curry",
                  TeamName = "Golden State Warriors",
                  GamesPlayed = 4,
                  FieldGoals = 30,
                  ThreePointer = 6
              },
              

Now further down in my main class I have a method used to add a new HockeyPlayer

static void addHockeyPlayer()
        {
            Console.WriteLine("\nAdding Hockey PLayer");
            Console.WriteLine("\nEnter Player Name:");
            bool valid = false;
            while (!valid)
            {
                string nameInput = Console.ReadLine();
                if (string.IsNullOrEmpty(nameInput) || Regex.IsMatch(nameInput, @"^\d+$"))
                {
                    Console.WriteLine("\nInvalid Input. Please try again");
                    Console.Write("Enter Player Name:");
                    valid = false;
                }
                else
                {
                    //new HockeyPlayer
                    //{
                        //PlayerId = 6,
                        //PlayerName = nameInput
                    //};
                    break;
                }
            }
            Console.WriteLine("Enter Player Team:");
            while (!valid)
            {
                string teamInput = Console.ReadLine();
                if (string.IsNullOrEmpty(teamInput) || Regex.IsMatch(teamInput, @"^\d+$"))
                {
                    Console.WriteLine("\nInvalid Input. Please try again");
                    Console.Write("Enter Player Name:");
                    valid = false;
                }
                else
                {
                    ////////

                }
            }
        }

As you can see, after every WriteLine(PlayerName,TeamName,GamesPlayed,Goals,Assists) I need to validate the Input. I'm not sure how I should be putting all the validated inputs together and then adding it to the List as a complete player?

Answer 1

UPDATE : so you can return a new HockeyPlayer object. I would also get rid of PlayerId property since the index in the list can represent this number:

public HockeyPlayer createHockeyPlayer() 
{
    HockeyPlayer hockeyPlayer = new HockeyPlayer();

    Console.WriteLine("\nAdding Hockey PLayer");

    while(true)
    {
        Console.WriteLine("\nEnter Player Name: ");
        hockeyPlayer.NameInput = Console.ReadLine();

        if(string.IsNullOrEmpty(hockeyPlayer.NameInput) || Regex.IsMatch(hockeyPlayer.NameInput, @"^\d+$"))
        {
            // complain about bad input
        }
        else
        {
            break;
        }
    }

    while(true)
    {
        Console.WriteLine("\nEnter Player Team: ");
        hockeyPlayer.TeamInput = Console.ReadLine();

        if(string.IsNullOrEmpty(hockeyPlayer.TeamInput) || Regex.IsMatch(hockeyPlayer.TeamInput, @"^\d+$"))
        {
            // complain about bad input
        }
        else
        {
            break;
        }
    }

     hockeyPlayer.GamesPlayed = 0;
     hockeyPlayer.Assists = 0;
     hockeyPlayer.Goals = 0;

    return hockeyPlayer;
}

And then you can add the HockeyPlayer outside of this method:

List<Player> players = new List<Player>();
players.Add(HockeyPlayer());

Answer 2

To avoid the repetitive validation code, you could extract it into a method that takes in a string as a prompt for the user and a Func<string, bool> that represents the function to be used to validate the input:

public static string GetStringFromUser(string prompt, Func<string, bool> validator = null)
{
    var isValid = true;
    string result;

    do
    {
        if (!isValid)
        {
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine("Invalid input, please try again.", ConsoleColor.Red);
            Console.ResetColor();
        }
        else isValid = false;

        Console.Write(prompt);
        result = Console.ReadLine();
    } while (validator != null && !validator.Invoke(result));

    return result;
}

We can do something similar for the int fields, to ensure they enter a number, and it isn't negative:

public static int GetIntFromUser(string prompt, Func<int, bool> validator = null)
{
    var isValid = true;
    int result;

    do
    {
        if (!isValid)
        {
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine("Invalid input, please try again.", ConsoleColor.Red);
            Console.ResetColor();
        }
        else isValid = false;

        Console.Write(prompt);
    } while (!int.TryParse(Console.ReadLine(), out result) ||
                (validator != null && !validator.Invoke(result)));

    return result;
}

Then, you can just use the result of these methods to populate the items in a new instance of the Player class:

static void AddHockeyPlayer(List<Player> players)
{
    Console.WriteLine("\nAdding Hockey PLayer");

    // Create some functions to validate input
    Func<int, bool> numberValidator = x => x >= 0;
    Func<string, bool> nameValidator = x => !string.IsNullOrEmpty(x) && 
        !Regex.IsMatch(x, @"^\d+$");

    // Make sure players isn't null
    if (players == null) players = new List<Player>();

    // Add a new player using our new methods to get the user input
    players.Add(new Player
    {
        PlayerName = GetStringFromUser("Enter player name: ", nameValidator),
        TeamName = GetStringFromUser("Enter team name: ", nameValidator),
        PlayerId = GetIntFromUser("Enter player id: ", numberValidator),
        Assists = GetIntFromUser("Enter number of assists: ", numberValidator),
        GamesPlayed = GetIntFromUser("Enter number of games played: ", numberValidator),
        Goals = GetIntFromUser("Enter number of goals: ", numberValidator)
    });
}

Then in you main method, you would just call it like:

AddHockeyPlayer(players);