按声明顺序对枚举进行排序 [英] Sort enums in declaration order
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问题描述
public enum CurrencyId
{
USD = 840,
UAH = 980,
RUR = 643,
EUR = 978,
KZT = 398,
UNSUPPORTED = 0
}
有什么方法可以按在 .cs 文件中声明的顺序对 Enum.GetValues(typeof(CurrencyId)).Cast
的结果进行排序(USD、UAH、EUR、KZT、UNSUPPORTED),而不是它们的底层代码?就我个人而言,我认为答案是否定的,因为原始顺序在二进制文件中丢失了,所以......我该如何实现任务?
Is there any way to sort results of Enum.GetValues(typeof(CurrencyId)).Cast<CurrencyId>()
by order they are declared in .cs file (USD, UAH, RUR, EUR, KZT, UNSUPPORTED), not by their underlying code? Personally, I believe the answer is 'no', because original order is lost in binaries, so... how can I implement the task?
推荐答案
这是带有自定义属性的版本:
Here is version with custom attribute:
[AttributeUsage(AttributeTargets.Field, AllowMultiple = false)]
public class EnumOrderAttribute : Attribute
{
public int Order { get; set; }
}
public static class EnumExtenstions
{
public static IEnumerable<string> GetWithOrder(this Enum enumVal)
{
return enumVal.GetType().GetWithOrder();
}
public static IEnumerable<string> GetWithOrder(this Type type)
{
if (!type.IsEnum)
{
throw new ArgumentException("Type must be an enum");
}
// caching for result could be useful
return type.GetFields()
.Where(field => field.IsStatic)
.Select(field => new
{
field,
attribute = field.GetCustomAttribute<EnumOrderAttribute>()
})
.Select(fieldInfo => new
{
name = fieldInfo.field.Name,
order = fieldInfo.attribute != null ? fieldInfo.attribute.Order : 0
})
.OrderBy(field => field.order)
.Select(field => field.name);
}
}
用法:
public enum TestEnum
{
[EnumOrder(Order=2)]
Second = 1,
[EnumOrder(Order=1)]
First = 4,
[EnumOrder(Order=3)]
Third = 0
}
var names = typeof(TestEnum).GetWithOrder();
var names = TestEnum.First.GetWithOrder();
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