c# - 至少一个对象必须实现 IComparable

Question

using System;
using System.Xml;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            SortedSet<Player> PlayerList = new SortedSet<Player>();

            while (true)
            {
                string Input;
                Console.WriteLine("What would you like to do?");
                Console.WriteLine("1. Create new player and score.");
                Console.WriteLine("2. Display Highscores.");
                Console.WriteLine("3. Write out to XML file.");
                Console.Write("Input Number: ");
                Input = Console.ReadLine();
                if (Input == "1")
                {
                    Player player = new Player();
                    string PlayerName;
                    string Score;

                    Console.WriteLine();
                    Console.WriteLine("-=CREATE NEW PLAYER=-");
                    Console.Write("Player name: ");
                    PlayerName = Console.ReadLine();
                    Console.Write("Player score: ");
                    Score = Console.ReadLine();

                    player.Name = PlayerName;
                    player.Score = Convert.ToInt32(Score);

                    //====================================
                    //ERROR OCCURS HERE
                    //====================================
                    PlayerList.Add(player);


                    Console.WriteLine("Player \"" + player.Name + "\" with the score of \"" + player.Score + "\" has been created successfully!" );
                    Console.WriteLine();
                }
                else
                {
                    Console.WriteLine("INVALID INPUT");
                }
            }
        }
    }
}

所以我不断收到“

At least one object must implement IComparable.

"当尝试添加第二个播放器时，第一个播放器有效，但第二个播放器无效。 我还必须使用 SortedSet，因为这是工作的要求，这是学校作业。

Answer 1

那么，您正在尝试使用 SortedSet<> ...这意味着您关心订购。但听上去你的Player类型未实现 IComparable<Player> .那么您希望看到什么样的排序顺序？

基本上，您需要告诉您的 Player编码如何将一个玩家与另一个玩家进行比较。或者，您可以实现 IComparer<Player>在其他地方，并将该比较传递给 SortedSet<> 的构造函数以指示您希望玩家的顺序。例如，您可以:

public class PlayerNameComparer : IComparer<Player>
{
    public int Compare(Player x, Player y)
    {
        // TODO: Handle x or y being null, or them not having names
        return x.Name.CompareTo(y.Name);
    }
}

然后:

// Note name change to follow conventions, and also to remove the
// implication that it's a list when it's actually a set...
SortedSet<Player> players = new SortedSet<Player>(new PlayerNameComparer());