C# 给枚举定义DescriptionAttribute，把枚举转换为键值对
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