C# 给枚举定义DescriptionAttribute,把枚举转换为键值对
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在C#中,枚举用来定状态值很方便,例如我定义一个叫做Season的枚举
public enum Season { Spring = 1, Summer = 2, Autumn = 3, Winter = 4 }
枚举名是不能出现空格,()-/等字符
我们想把Spring显示为春天,我们要自己定义说明信息,我们可以使用DescriptionAttribute,如下
public enum Season { [Description("春 天")] Spring = 1, [Description("夏 天")] Summer = 2, //[Description("秋 天")] Autumn = 3, [Description("冬 天")] Winter = 4 }
下面我们来写个扩展方法,来得到枚举的说明信息,如下
/// <summary> /// 扩展方法,获得枚举的Description /// </summary> /// <param name="value">枚举值</param> /// <param name="nameInstead">当枚举值没有定义DescriptionAttribute,是否使用枚举名代替,默认是使用</param> /// <returns>枚举的Description</returns> public static string GetDescription(this Enum value, Boolean nameInstead = true) { Type type = value.GetType(); string name = Enum.GetName(type, value); if (name == null) { return null; } FieldInfo field = type.GetField(name); DescriptionAttribute attribute = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute)) as DescriptionAttribute; if (attribute == null&&nameInstead == true) { return name; } return attribute == null ? null : attribute.Description; }
把枚举转换为键值对集合
/// <summary> /// 把枚举转换为键值对集合 /// </summary> /// <param name="enumType">枚举类型</param> /// <param name="getText">获得值得文本</param> /// <returns>以枚举值为key,枚举文本为value的键值对集合</returns> public static Dictionary<Int32, String> EnumToDictionary(Type enumType, Func<Enum, String> getText) { if (!enumType.IsEnum) { throw new ArgumentException("传入的参数必须是枚举类型!", "enumType"); } Dictionary<Int32, String> enumDic = new Dictionary<int, string>(); Array enumValues = Enum.GetValues(enumType); foreach (Enum enumValue in enumValues) { Int32 key = Convert.ToInt32(enumValue); String value = getText(enumValue); enumDic.Add(key, value); } return enumDic; }
我们把上面两个方法放入名为EnumUtil的静态类中。
下面是使用方法
public enum Season { [Description("春 天")] Spring = 1, [Description("夏 天")] Summer = 2, //[Description("秋 天")] Autumn = 3, [Description("冬 天")] Winter = 4 } class Program { static void Main(string[] args) { Season spring = Season.Spring; //打印枚举名 Console.WriteLine(spring.ToString()); //打印枚举说明 Console.WriteLine(spring.GetDescription()); //枚举转换为键值对集合 Dictionary<Int32, String> dic = EnumUtil.EnumToDictionary(typeof(Season), e => e.GetDescription()); PrintDic(dic); dic = EnumUtil.EnumToDictionary(typeof(Season), e => e.GetDescription(false)); PrintDic(dic); dic = EnumUtil.EnumToDictionary(typeof(Season), e => e.ToString()); PrintDic(dic); dic = EnumUtil.EnumToDictionary(typeof(Season), e => Enum.GetName(typeof(Season), e)); PrintDic(dic); Console.ReadLine(); } private static void PrintDic(Dictionary<Int32, String> dic) { foreach (KeyValuePair<Int32,String> item in dic) { Console.WriteLine("Key:{0}-----Value:{1}", item.Key, item.Value); } } }
输出结果如下
Spring
春 天
Key:1-----Value:春 天
Key:2-----Value:夏 天
Key:3-----Value:Autumn
Key:4-----Value:冬 天
Key:1-----Value:春 天
Key:2-----Value:夏 天
Key:3-----Value:
Key:4-----Value:冬 天
Key:1-----Value:Spring
Key:2-----Value:Summer
Key:3-----Value:Autumn
Key:4-----Value:Winter
Key:1-----Value:Spring
Key:2-----Value:Summer
Key:3-----Value:Autumn
Key:4-----Value:Winter
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