从描述属性获取枚举

可能重复：
通过描述属性查找枚举值

我有一个通用的扩展方法，从Enum获取Description属性：

 enum Animal { [Description("")] NotSet = 0, [Description("Giant Panda")] GiantPanda = 1, [Description("Lesser Spotted Anteater")] LesserSpottedAnteater = 2 } public static string GetDescription(this Enum value) { FieldInfo field = value.GetType().GetField(value.ToString()); DescriptionAttribute attribute = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute)) as DescriptionAttribute; return attribute == null ? value.ToString() : attribute.Description; } 

所以我可以做…

 string myAnimal = Animal.GiantPanda.GetDescription(); // = "Giant Panda" 

现在，我试图在另一个方向上计算等价的函数，比如…

 Animal a = (Animal)Enum.GetValueFromDescription("Giant Panda", typeof(Animal)); 

Answer 1

 public static class EnumEx { public static T GetValueFromDescription<T>(string description) { var type = typeof(T); if(!type.IsEnum) throw new InvalidOperationException(); foreach(var field in type.GetFields()) { var attribute = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute)) as DescriptionAttribute; if(attribute != null) { if(attribute.Description == description) return (T)field.GetValue(null); } else { if(field.Name == description) return (T)field.GetValue(null); } } throw new ArgumentException("Not found.", "description"); // or return default(T); } } 

用法：

 var panda = EnumEx.GetValueFromDescription<Animal>("Giant Panda"); 

Answer 2

而不是扩展方法，只需要尝试几个静态方法

 public static class Utility { public static string GetDescriptionFromEnumValue(Enum value) { DescriptionAttribute attribute = value.GetType() .GetField(value.ToString()) .GetCustomAttributes(typeof (DescriptionAttribute), false) .SingleOrDefault() as DescriptionAttribute; return attribute == null ? value.ToString() : attribute.Description; } public static T GetEnumValueFromDescription<T>(string description) { var type = typeof(T); if (!type.IsEnum) throw new ArgumentException(); FieldInfo[] fields = type.GetFields(); var field = fields .SelectMany(f => f.GetCustomAttributes( typeof(DescriptionAttribute), false), ( f, a) => new { Field = f, Att = a }) .Where(a => ((DescriptionAttribute)a.Att) .Description == description).SingleOrDefault(); return field == null ? default(T) : (T)field.Field.GetRawConstantValue(); } } 

并在这里使用

 var result1 = Utility.GetDescriptionFromEnumValue( Animal.GiantPanda); var result2 = Utility.GetEnumValueFromDescription<Animal>( "Lesser Spotted Anteater"); 

Answer 3

除非你有一个Web服务，否则这个解决scheme工作的很好。

由于说明属性不可序列化，因此您需要执行以下操作。

 [DataContract] public enum ControlSelectionType { [EnumMember(Value = "Not Applicable")] NotApplicable = 1, [EnumMember(Value = "Single Select Radio Buttons")] SingleSelectRadioButtons = 2, [EnumMember(Value = "Completely Different Display Text")] SingleSelectDropDownList = 3, } public static string GetDescriptionFromEnumValue(Enum value) { EnumMemberAttribute attribute = value.GetType() .GetField(value.ToString()) .GetCustomAttributes(typeof(EnumMemberAttribute), false) .SingleOrDefault() as EnumMemberAttribute; return attribute == null ? value.ToString() : attribute.Value; } 

Answer 4

应该是相当简单的，它只是你以前的方法相反;

 public static int GetEnumFromDescription(string description, Type enumType) { foreach (var field in enumType.GetFields()) { DescriptionAttribute attribute = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute))as DescriptionAttribute; if(attribute == null) continue; if(attribute.Description == description) { return (int) field.GetValue(null); } } return 0; } 

用法：

 Console.WriteLine((Animal)GetEnumFromDescription("Giant Panda",typeof(Animal))); 

Answer 5

因为它是一个静态类，所以不能扩展Enum 。 你只能扩展一个types的实例。 考虑到这一点，你将不得不自己创build一个静态方法来做到这一点; 当与现有方法GetDescription结合使用时，以下方法应该可以工作：

 public static class EnumHelper { public static T GetEnumFromString<T>(string value) { if (Enum.IsDefined(typeof(T), value)) { return (T)Enum.Parse(typeof(T), value, true); } else { string[] enumNames = Enum.GetNames(typeof(T)); foreach (string enumName in enumNames) { object e = Enum.Parse(typeof(T), enumName); if (value == GetDescription((Enum)e)) { return (T)e; } } } throw new ArgumentException("The value '" + value + "' does not match a valid enum name or description."); } } 

它的用法是这样的：

 Animal giantPanda = EnumHelper.GetEnumFromString<Animal>("Giant Panda"); 

Answer 6

您需要迭代Animal中的所有枚举值，并返回与您需要的描述相匹配的值。