c# - Get enum from enum attribute

最新推荐文章于 2021-03-15 14:01:28 发布

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本文介绍了一种方法，用于根据枚举值上的DescriptionAttribute获取对应的枚举成员。通过定义扩展方法，可以方便地实现这一功能，使得在.NET应用程序中能够更加灵活地使用枚举类型。

DescriptionAttribute gives the enum or other qualified types some description which is human readable.

such as

    public enum Testing
    {
        [Description("David Gouge")]
        Dave = 1,
        [Description("Peter Gouge")]
        Pete = 2,
        [Description("Marie Gouge")]
        Ree = 3
    }

But, given this, how do you find the an Enum value based on the the description value atached to the field?

you can use this

            var descriptionToMatch = new DescriptionAttribute("David Gouge");
 
            Testing testing = Enum.GetValues(typeof (Testing))
                                  .Cast<Testing>()
                                  .Where(v => descriptionToMatch.Equals(v.GetDescription()))
                                  .FirstOrDefault();

In order to use that you will need to define some extension method, I hvae wrote up two. (the Linq one is the one that I wrote for mysef.)

    static class StaticEnumHelper
    {
        public static DescriptionAttribute GetDescription(this Enum enu)
        {
            DescriptionAttribute attr = enu.GetType()
                                           .GetField(enu.ToString())
                                           .GetCustomAttributes(typeof(DescriptionAttribute), false)
                                           .SingleOrDefault() as DescriptionAttribute;
            return attr ?? null;
        }
 
        public static string GetDescription2(this Enum value)
        {
            if (value == null)
            {
                throw new ArgumentNullException("value");
            }
 
            string description = value.ToString();
            FieldInfo fieldInfo = value.GetType().GetField(description);
            DescriptionAttribute[] attributes =
               (DescriptionAttribute[])
             fieldInfo.GetCustomAttributes(typeof(DescriptionAttribute), false);
 
            if (attributes != null && attributes.Length > 0)
            {
                description = attributes[0].Description;
            }
            return description;
        }
    }

Referneces:

Finding an enum value by its Description Attribute [Duplicate]

Get Enum from enum attribute:

DescriptionAttribute class: