C#枚举的使用

傷城~ 2021-09-19 20:18 485阅读 0赞

一个枚举，它表示一组有限的值，对可能的值进行约束。

**1、定义一个枚举**

//枚举
    public enum Genders
    {
        Male = 1,
        Female = 2
    }

**2、获取枚举的值**

//获取枚举的值
    Genders genders = Genders.Female;
    int value = (int)genders;           //2
    string key = genders.ToString();    //Female

**3、从一个字符串转换成枚举**

//从一个字符串转换成枚举
    Genders gender = (Genders)Enum.Parse(typeof(Genders), "Female");
    Console.WriteLine(gender);

**4、从一个枚举值转换成枚举**

//从一个枚举值转换成枚举
    Genders gender = (Genders)Enum.ToObject(typeof(Genders), 2);
    Console.WriteLine(gender);

**5、从一个字符串转换枚举值**

//从一个字符串转换枚举值
    int valus = (int)(Enum.Parse(typeof(Genders), "Female"));
    Console.WriteLine(valus);

**6、判断是否有效枚举值**

//判断是否有效枚举值
    bool b1 = System.Enum.IsDefined(typeof(Genders), 2);           //True
    bool b2 = System.Enum.IsDefined(typeof(Genders), "Female");    //True
    bool b3 = System.Enum.IsDefined(typeof(Genders), 99);          //False
    bool b4 = System.Enum.IsDefined(typeof(Genders), "ABC");       //False

**7、枚举的遍历**

//枚举的遍历
    public static Dictionary<string, int> GetGenders()
    {
        Dictionary<string, int> result = new Dictionary<string, int>();
        string key = "";
        int value = 0;
        foreach (int gender in Enum.GetValues(typeof(Genders)))
        {
            key = Enum.GetName(typeof(Genders), gender);
            value = gender;
            result.Add(key, value);
        }
        return result;
    }

**8、枚举公共处理类**

/// <summary>
    /// 枚举公共处理类
    /// </summary>
    public class EnumHandler<T>
    {
        /// <summary>
        /// 转换成枚举
        /// </summary>
        public T ToEnum(object value)
        {
            int i = 0;
            if (int.TryParse(value.ToString(), out i))
            {
                return (T)Enum.ToObject(typeof(T), i);
            }
            else
            {
                return (T)Enum.Parse(typeof(T), value.ToString());
            }
        }
    
        /// <summary>
        /// 判断是否有效枚举值
        /// </summary>
        public bool IsEnumValue(Object value)
        {
            int i = 0;
            if (int.TryParse(value.ToString(), out i))
            {
                return System.Enum.IsDefined(typeof(T), i);
            }
            else
            {
                return System.Enum.IsDefined(typeof(T), value);
            }
        }
    
        /// <summary>
        /// 枚举的遍历
        /// </summary>
        public Dictionary<string, int> ToDictionary()
        {
            Dictionary<string, int> result = new Dictionary<string, int>();
            string key = "";
            int value = 0;
            foreach (int gender in Enum.GetValues(typeof(T)))
            {
                key = Enum.GetName(typeof(T), gender);
                value = gender;
                result.Add(key, value);
            }
            return result;
        }
    }

**测试：**

static void Main(string[] args)
    {
        object value = 2;
        EnumHandler<Genders> enumHandler = new EnumHandler<Genders>();
        if (enumHandler.IsEnumValue(value))
        {
            Genders gender = enumHandler.ToEnum(value);
            Console.WriteLine(gender);
        }
        else
        {
            Console.WriteLine("无效的枚举值");
        }
        Console.ReadLine();
    }