C#中正确使用enum累做Key的姿势

C#中自定义enum，然后将其作为Dictionary的Key，通常的做法如下:

using System;
using System.Text;
using System.Collections.Generic;

namespace ConsoleApplication1
{
    enum ClothType
    {
        Hair,
        Coat,
        Shoes,
    }

    class Cloth
    {
 
    }

    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<ClothType, Cloth> dicCloth = new Dictionary<ClothType, Cloth>();
            dicCloth.Add(ClothType.Coat, new Cloth());
            Console.ReadKey();
        }
    }
}

但是这样在调用Add方法的时候，会间接地造成封箱操作，这样就带来了不必要的性能消耗。当然了，不只是Add方法。

下面的方法可以解决该问题:

using System;
using System.Text;
using System.Collections.Generic;
using System.Collections;

namespace ConsoleApplication1
{
    enum ClothType
    {
        Hair,
        Coat,
        Shoes,
    }

    //新加比较器类
    class ClothTypeEnumComparer : IEqualityComparer<ClothType>
    {
        public bool Equals(ClothType x, ClothType y)
        {
            return x == y;          //x.Equals(y);  注意这里不要使用Equals方法，因为也会造成封箱操作
        }

        public int GetHashCode(ClothType x)
        {
            return (int)x;
        }
    }

    class Cloth
    {
 
    }

    class Program
    {
        static void Main(string[] args)
        {
            ClothTypeEnumComparer myEnumComparer = new ClothTypeEnumComparer();         //在实际项目中，比较器可以保存一份，方便服用，测试暂且如此
            Dictionary<ClothType, Cloth> dicCloth = new Dictionary<ClothType, Cloth>(myEnumComparer);
            dicCloth.Add(ClothType.Coat, new Cloth());
            Console.ReadKey();
        }
    }
}