枚举类型使用

1.首先我们建立一个枚举类。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
namespace ConsoleApp3
{
    public enum Fruit
    {
        apple,
        peach,
        watermelon,
        banana,
        orange
    }
}

2.代码调用

using ConsoleApp3;
Console.WriteLine(Fruit.orange);
Console.WriteLine("Hello, World!");

3.当我们要使用中文的时候，这时候要进行变化，使用特性

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
 
namespace ConsoleApp3
{
    public enum Fruit
    {
        [Description("苹果")]
        apple,
        [Description("桃子")]
        peach,
        [Description("西瓜")]
        watermelon,
        [Description("香蕉")]
        banana,
        [Description("橘子")]
        orange
    }
    static class EnumExtensions
    {
        public static string GetDescription(this Enum val)
        {
            var field = val.GetType().GetField(val.ToString());
            if (field == null)
                return val.ToString();
            var customAttribute = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute));     //使用反射，反射效率低
            return customAttribute == null ? val.ToString() : ((DescriptionAttribute)customAttribute).Description;
 
        }
    }
}

4.代码调用

using ConsoleApp3;
Console.WriteLine(Fruit.orange);
Console.WriteLine(Fruit.orange.GetDescription());
Console.WriteLine("Hello, World!");

5.如果我们有很多种类的水果的话，并且分类的话。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
 
namespace ConsoleApp3
{
    public enum Fruit
    {
        [levelOne("一级")]
        [Description("苹果")]
        apple,
        [levelOne("二级")]
        [Description("桃子")]
        peach,
        [Description("西瓜")]
        watermelon,
        [levelOne("三级")]
        [Description("香蕉")]
        banana,
        [levelOne("三级")]
        [Description("橘子")]
        orange
    }
    static class EnumExtensions
    {
        public static string GetDescription(this Enum val)
        {
            var field = val.GetType().GetField(val.ToString());
            if (field == null)
                return val.ToString();
            var customAttribute = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute));     //使用反射，反射效率低
            return customAttribute == null ? val.ToString() : ((DescriptionAttribute)customAttribute).Description;
        }
        public static string Getlevel(this Enum val)
        {
            var field = val.GetType().GetField(val.ToString());
            if(field == null)
                return val.ToString();
            var customAttribute = Attribute.GetCustomAttribute(field, typeof(levelOne));
            return customAttribute == null ? val.ToString() : ((levelOne)customAttribute).Data;
        }
    }
    public class levelOne : Attribute
    {
        public string Data { get; set; }
        public levelOne() { }
        public levelOne(string data)
        {
            Data = data;
        }
    }
}

6.代码调用

using ConsoleApp3;
Console.WriteLine(Fruit.orange);
Console.WriteLine(Fruit.orange.GetDescription());
Console.WriteLine(Fruit.orange.Getlevel());
Console.WriteLine(Fruit.apple.Getlevel());
Console.WriteLine("Hello, World!");