Question

类Coin具有以下属性：MoneyType, Value, Diameter。

MoneyType是枚举：

enum CoinType
    {
        Cent,
        Nickel,
        Dime,
        QuarterDollar,
        HalfDollar,
        Dollar,        
    }

每个MoneyType应具有特定的值和直径，例如Cent：Value = 1和Diameter = 19，因此如果我指定MoneyType，则应根据MoneyType自动分配Value和Diameter。不知道该怎么做。也许某种枚举元组？

例如：

enum CoinType
        {
            (Cent, 1, 19),
            (Nickel, 10, 21),
.....            
        }

我只想要每个MoneyType都有特定的值和直径。

Answer 1

另一种方法是实现自定义枚举。根据您的需要修改来源。

#region Base Abstract Class

public abstract class EnumBaseType<T> where T : EnumBaseType<T>
{
    protected static List<T> enumValues = new List<T>();

    public readonly string Key;
    public readonly int Value;
    public readonly int Diameter;

    public EnumBaseType(string key, int value, int diameter)
    {
        Key = key;
        Value = value;
        Diameter = diameter;
        enumValues.Add((T)this);
    }

    protected static System.Collections.ObjectModel.ReadOnlyCollection<T> GetBaseValues()
    {
        return enumValues.AsReadOnly();
    }

    protected static T GetBaseByKey(string key)
    {
        foreach (T t in enumValues)
        {
            if (t.Key == key) return t;
        }
        return null;
    }
}

#endregion

#region Enhanced Enum Sample

public class MoneyType : EnumBaseType<MoneyType>
{
    public static readonly MoneyType Cent = new MoneyType("Cent", 1, 19);
    public static readonly MoneyType Nickel = new MoneyType("Nickel", 5, 25);
    public static readonly MoneyType Dime = new MoneyType("Dime", 10, 30);
    public static readonly MoneyType QuarterDollar = new MoneyType("QuarterDollar", 25, 15);
    public static readonly MoneyType HalfDollar = new MoneyType("HalfDollar", 50, 100);
    public static readonly MoneyType Dollar = new MoneyType("Dollar", 100, 29);

    public MoneyType(string key, int value, int diameter)
        : base(key, value, diameter)
    {
    }

    public static ReadOnlyCollection<MoneyType> GetValues()
    {
        return GetBaseValues();
    }

    public static MoneyType GetByKey(string key)
    {
        return GetBaseByKey(key);
    }
}

#endregion


public class Test
{
    public Test()
    {
        foreach (MoneyType rating in MoneyType.GetValues())
        {
            Console.Out.WriteLine("Key:{0} Value:{1}", rating.Key, rating.Value);

            if (rating == MoneyType.Dollar)
            {
                Console.Out.WriteLine("This is a dollar!");
            }
        }

        foreach (MoneyType rating in MoneyType.GetValues())
        {
            if (rating.Diameter == MoneyType.Nickel.Diameter)
            {
                Console.Out.WriteLine("This is a Nickel diameter!");
            }
        }
    }
}

source

修改

刚刚发现：Type-safe-enum pattern

Answer 2

枚举只不过是带有名称的INT值。它只存储一个离散值。你想要使用的是一个类。

更新：

抱歉，关于我的错误。自从我使用C＃以来，实际上已经有一段时间了。为了弥补这一点，我已经写出了我的意思：

enum CoinType {
    Cent=1,
    Nickel=5,
    Dime=10,
    QuarterDollar=25,
    HalfDollar=50,
    Dollar=100,
}

class Coin {
    public CoinType type;

    public int Diameter { 
        get { 
            switch (type) {
                case CoinType.Cent: return 19;
                case CoinType.Nickel: return 25;
                case CoinType.Dime: return 20;
                case CoinType.QuarterDollar: return 40;
                case CoinType.HalfDollar: return 40;
                case CoinType.Dollar: return 40;
            }
            return 0;
        } 
    }
}

Answer 3

您可以在枚举成员上添加自定义属性。

enum CoinType
{
    [Value=1]
    [Diameter=19]
    Cent,

    ...
}

然后，您可以使用反射从属性中获取信息。

Answer 4

您只需要从CoinType到直径的映射，以及从CoinType到value的另一个映射。两者都可以通过简单的switch语句完成。

enum CoinType
{
    Cent,
    Nickel,
    Dime,
    QuarterDollar,
    HalfDollar,
    Dollar,  
}

static class CoinTypeExts
{
    static double Diameter(this CoinType coinType)
    {
        switch (coinType)
        {
            case Cent: return 19;
            etc...
        }
    }

    static double Value(this CoinType coinType)
    {
        switch (coinType)
        {
            case CoinType.Cent: return 1.0;
            etc...
        }
    }
}

货币类型枚举

4 个答案: