C# 获取Enum'的属性;s值
我想知道是否可以获取C# 获取Enum'的属性;s值,c#,reflection,enums,.net-attributes,C#,Reflection,Enums,.net Attributes,我想知道是否可以获取enum值的属性,而不是enum本身的属性?例如,假设我有以下enum: using System.ComponentModel; // for DescriptionAttribute enum FunkyAttributesEnum { [Description("Name With Spaces1")] NameWithoutSpaces1, [Description("Name With Spaces2")] NameWith
enum
值的属性,而不是enum
本身的属性?例如,假设我有以下enum
:
using System.ComponentModel; // for DescriptionAttribute
enum FunkyAttributesEnum
{
[Description("Name With Spaces1")]
NameWithoutSpaces1,
[Description("Name With Spaces2")]
NameWithoutSpaces2
}
我想要的是给定枚举类型,生成枚举字符串值的2元组及其描述
public static string GetAttributeDescription(this Enum enumValue)
{
var attribute = enumValue.GetAttributeOfType<DescriptionAttribute>();
return attribute == null ? String.Empty : attribute.Description;
}
价值很简单:
Array values = System.Enum.GetValues(typeof(FunkyAttributesEnum));
foreach (int value in values)
Tuple.Value = Enum.GetName(typeof(FunkyAttributesEnum), value);
但如何获得description属性的值来填充
Tuple.Desc
?如果属性属于enum
本身,我可以考虑如何执行该操作,但我不知道如何从enum
的值中获取它,这应该满足您的需要
var enumType=typeof(funkyattributenum);
var memberInfos=enumType.GetMember(funkyattributenum.NameWithoutSpaces1.ToString());
变量enumValueMemberInfo=memberInfos.FirstOrDefault(m=>m.DeclaringType==enumType);
var valueAttributes=
enumValueMemberInfo.GetCustomAttributes(typeof(DescriptionAttribute),false);
变量说明=((DescriptionAttribute)valueAttributes[0])。说明;
或者,您可以执行以下操作:
Dictionary<FunkyAttributesEnum, string> description = new Dictionary<FunkyAttributesEnum, string>()
{
{ FunkyAttributesEnum.NameWithoutSpaces1, "Name With Spaces1" },
{ FunkyAttributesEnum.NameWithoutSpaces2, "Name With Spaces2" },
};
string s = description[FunkyAttributesEnum.NameWithoutSpaces1];
Console.WriteLine(Days.Mon.ToName());
在我看来,这是一种更有效的方法来完成您想要完成的任务,因为不需要反射。这是一种使用lambda进行选择的通用实现
public static Expected GetAttributeValue<T, Expected>(this Enum enumeration, Func<T, Expected> expression)
where T : Attribute
{
T attribute =
enumeration
.GetType()
.GetMember(enumeration.ToString())
.Where(member => member.MemberType == MemberTypes.Field)
.FirstOrDefault()
.GetCustomAttributes(typeof(T), false)
.Cast<T>()
.SingleOrDefault();
if (attribute == null)
return default(Expected);
return expression(attribute);
}
public静态预期GetAttributeValue(此枚举枚举,Func表达式)
其中T:Attribute
{
T属性=
列举
.GetType()
.GetMember(枚举.ToString())
.Where(member=>member.MemberType==MemberTypes.Field)
.FirstOrDefault()
.GetCustomAttributes(typeof(T),false)
.Cast()
.SingleOrDefault();
if(属性==null)
返回默认值(预期值);
返回表达式(属性);
}
可以这样称呼:
string description = targetLevel.GetAttributeValue<DescriptionAttribute, string>(x => x.Description);
string description=targetLevel.GetAttributeValue(x=>x.description);
这段代码应该为任何枚举提供一个很好的扩展方法,让您可以检索泛型属性。我相信它与上面的lambda函数不同,因为它使用起来更简单,而且稍微有些复杂,您只需要传入泛型类型
public static class EnumHelper
{
/// <summary>
/// Gets an attribute on an enum field value
/// </summary>
/// <typeparam name="T">The type of the attribute you want to retrieve</typeparam>
/// <param name="enumVal">The enum value</param>
/// <returns>The attribute of type T that exists on the enum value</returns>
/// <example><![CDATA[string desc = myEnumVariable.GetAttributeOfType<DescriptionAttribute>().Description;]]></example>
public static T GetAttributeOfType<T>(this Enum enumVal) where T:System.Attribute
{
var type = enumVal.GetType();
var memInfo = type.GetMember(enumVal.ToString());
var attributes = memInfo[0].GetCustomAttributes(typeof(T), false);
return (attributes.Length > 0) ? (T)attributes[0] : null;
}
}
公共静态类EnumHelper
{
///
///获取枚举字段值的属性
///
///要检索的属性的类型
///枚举值
///枚举值上存在的T类型属性
///()说明;]>
公共静态T GetAttributeOfType(此枚举enumVal),其中T:System.Attribute
{
var type=enumVal.GetType();
var memInfo=type.GetMember(enumVal.ToString());
var attributes=memInfo[0].GetCustomAttributes(typeof(T),false);
返回(attributes.Length>0)?(T)属性[0]:空;
}
}
我实现了这个扩展方法来从枚举值获取描述。它适用于所有类型的枚举
public static class EnumExtension
{
public static string ToDescription(this System.Enum value)
{
FieldInfo fi = value.GetType().GetField(value.ToString());
var attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
return attributes.Length > 0 ? attributes[0].Description : value.ToString();
}
}
除此之外,我还进一步创建了一个更专门的扩展方法,该扩展方法提供了对它的描述
public static string GetAttributeDescription(this Enum enumValue)
{
var attribute = enumValue.GetAttributeOfType<DescriptionAttribute>();
return attribute == null ? String.Empty : attribute.Description;
}
这将使您的代码更具可读性 下面是从显示属性获取信息的代码。它使用泛型方法来检索属性。如果未找到该属性,它会将枚举值转换为字符串,并将pascal/camel大小写转换为title大小写(获得代码)
公共静态类EnumHelper
{
//如果
//enum有一个,否则使用转换为标题大小写的值。
公共静态字符串GetDisplayName(此TEnum值)
其中TEnum:struct,i可转换
{
var attr=value.GetAttributeOfType();
返回attr==null?value.ToString().ToSpacedTitleCase():attr.Name;
}
//如果
//enum有一个,否则使用转换为标题大小写的值。
公共静态字符串GetDisplayShortName(此TEnum值)
其中TEnum:struct,i可转换
{
var attr=value.GetAttributeOfType();
返回attr==null?value.ToString().ToSpacedTitleCase():attr.ShortName;
}
///
///获取枚举字段值的属性
///
///枚举类型
///要检索的属性的类型
///枚举值
///枚举值上存在的T类型属性
私有静态T GetAttributeOfType(此TEnum值)
其中TEnum:struct,i可转换
其中T:Attribute
{
返回值。GetType()
.GetMember(value.ToString())
.First()
.GetCustomAttributes(false)
第()类
.LastOrDefault();
}
}
这是字符串转换为标题大小写的扩展方法:
/// <summary>
/// Converts camel case or pascal case to separate words with title case
/// </summary>
/// <param name="s"></param>
/// <returns></returns>
public static string ToSpacedTitleCase(this string s)
{
//https://stackoverflow.com/a/155486/150342
CultureInfo cultureInfo = Thread.CurrentThread.CurrentCulture;
TextInfo textInfo = cultureInfo.TextInfo;
return textInfo
.ToTitleCase(Regex.Replace(s,
"([a-z](?=[A-Z0-9])|[A-Z](?=[A-Z][a-z]))", "$1 "));
}
//
///将camel大小写或pascal大小写转换为带标题大小写的独立单词
///
///
///
公共静态字符串ToSpacedTitleCase(此字符串为s)
{
//https://stackoverflow.com/a/155486/150342
CultureInfo CultureInfo=Thread.CurrentThread.CurrentCulture;
TextInfo TextInfo=cultureInfo.TextInfo;
返回文本信息
.ToTitleCase(正则表达式替换),
“([a-z](?=[a-Z0-9])|[a-z](?=[a-z][a-z])”,“$1”);
}
此扩展方法将使用其XmlEnumAttribute获取枚举值的字符串表示形式。如果不存在XmlEnumAttribute,则返回enum.ToString()
public静态字符串tostringsingXmlEnumAttribute(此Enumt值)
其中T:struct,IConvertible
{
if(!typeof(T).IsEnum)
{
抛出新ArgumentException(“T必须是枚举类型”);
}
字符串名;
var类型=类型(T);
var memInfo=type.GetMember(enumValue.ToString());
如果(memInfo.Length==1)
{
var attributes=memInfo[0]。GetCustomAttributes(typeof(System.Xml.Serialization.XmlEnumAttribute),false
/// <summary>
/// Converts camel case or pascal case to separate words with title case
/// </summary>
/// <param name="s"></param>
/// <returns></returns>
public static string ToSpacedTitleCase(this string s)
{
//https://stackoverflow.com/a/155486/150342
CultureInfo cultureInfo = Thread.CurrentThread.CurrentCulture;
TextInfo textInfo = cultureInfo.TextInfo;
return textInfo
.ToTitleCase(Regex.Replace(s,
"([a-z](?=[A-Z0-9])|[A-Z](?=[A-Z][a-z]))", "$1 "));
}
public static string ToStringUsingXmlEnumAttribute<T>(this T enumValue)
where T: struct, IConvertible
{
if (!typeof(T).IsEnum)
{
throw new ArgumentException("T must be an enumerated type");
}
string name;
var type = typeof(T);
var memInfo = type.GetMember(enumValue.ToString());
if (memInfo.Length == 1)
{
var attributes = memInfo[0].GetCustomAttributes(typeof(System.Xml.Serialization.XmlEnumAttribute), false);
if (attributes.Length == 1)
{
name = ((System.Xml.Serialization.XmlEnumAttribute)attributes[0]).Name;
}
else
{
name = enumValue.ToString();
}
}
else
{
name = enumValue.ToString();
}
return name;
}
using System;
using System.ComponentModel;
public static class EnumExtensions {
// This extension method is broken out so you can use a similar pattern with
// other MetaData elements in the future. This is your base method for each.
public static T GetAttribute<T>(this Enum value) where T : Attribute {
var type = value.GetType();
var memberInfo = type.GetMember(value.ToString());
var attributes = memberInfo[0].GetCustomAttributes(typeof(T), false);
return attributes.Length > 0
? (T)attributes[0]
: null;
}
// This method creates a specific call to the above method, requesting the
// Description MetaData attribute.
public static string ToName(this Enum value) {
var attribute = value.GetAttribute<DescriptionAttribute>();
return attribute == null ? value.ToString() : attribute.Description;
}
}
using System.ComponentModel;
public enum Days {
[Description("Sunday")]
Sun,
[Description("Monday")]
Mon,
[Description("Tuesday")]
Tue,
[Description("Wednesday")]
Wed,
[Description("Thursday")]
Thu,
[Description("Friday")]
Fri,
[Description("Saturday")]
Sat
}
Console.WriteLine(Days.Mon.ToName());
var day = Days.Mon;
Console.WriteLine(day.ToName());
[AttributeUsage(AttributeTargets.Field,AllowMultiple = false)]
public class EnumDisplayName : Attribute
{
public string Name { get; private set; }
public EnumDisplayName(string name)
{
Name = name;
}
}
public static class EnumHelper
{
public static string EnumDisplayName(this HtmlHelper helper,EPriceType priceType)
{
//Get every fields from enum
var fields = priceType.GetType().GetFields();
//Foreach field skipping 1`st fieldw which keeps currently sellected value
for (int i = 0; i < fields.Length;i++ )
{
//find field with same int value
if ((int)fields[i].GetValue(priceType) == (int)priceType)
{
//get attributes of found field
var attributes = fields[i].GetCustomAttributes(false);
if (attributes.Length > 0)
{
//return name of found attribute
var retAttr = (EnumDisplayName)attributes[0];
return retAttr.Name;
}
}
}
//throw Error if not found
throw new Exception("Błąd podczas ustalania atrybutów dla typu ceny allegro");
}
}
public static IDictionary<string, int> ToDictionary(this Type enumType)
{
return Enum.GetValues(enumType)
.Cast<object>()
.ToDictionary(v => ((Enum)v).ToEnumDescription(), k => (int)k);
}
var dic = typeof(ActivityType).ToDictionary();
public static string ToEnumDescription(this Enum en) //ext method
{
Type type = en.GetType();
MemberInfo[] memInfo = type.GetMember(en.ToString());
if (memInfo != null && memInfo.Length > 0)
{
object[] attrs = memInfo[0].GetCustomAttributes(typeof(DescriptionAttribute), false);
if (attrs != null && attrs.Length > 0)
return ((DescriptionAttribute)attrs[0]).Description;
}
return en.ToString();
}
public enum ActivityType
{
[Description("Drip Plan Email")]
DripPlanEmail = 1,
[Description("Modification")]
Modification = 2,
[Description("View")]
View = 3,
[Description("E-Alert Sent")]
EAlertSent = 4,
[Description("E-Alert View")]
EAlertView = 5
}
public static DisplayAttribute GetDisplayAttributesFrom(this Enum enumValue, Type enumType)
{
return enumType.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>();
}
public enum ModesOfTransport
{
[Display(Name = "Driving", Description = "Driving a car")] Land,
[Display(Name = "Flying", Description = "Flying on a plane")] Air,
[Display(Name = "Sea cruise", Description = "Cruising on a dinghy")] Sea
}
void Main()
{
ModesOfTransport TransportMode = ModesOfTransport.Sea;
DisplayAttribute metadata = TransportMode.GetDisplayAttributesFrom(typeof(ModesOfTransport));
Console.WriteLine("Name: {0} \nDescription: {1}", metadata.Name, metadata.Description);
}
Name: Sea cruise
Description: Cruising on a dinghy
public static class Program
{
static void Main(string[] args)
{
// display the description attribute from the enum
foreach (Colour type in (Colour[])Enum.GetValues(typeof(Colour)))
{
Console.WriteLine(EnumExtensions.ToName(type));
}
// Get the array from the description
string xStr = "Yellow";
Colour thisColour = EnumExtensions.FromName<Colour>(xStr);
Console.ReadLine();
}
public enum Colour
{
[Description("Colour Red")]
Red = 0,
[Description("Colour Green")]
Green = 1,
[Description("Colour Blue")]
Blue = 2,
Yellow = 3
}
}
public static class EnumExtensions
{
// This extension method is broken out so you can use a similar pattern with
// other MetaData elements in the future. This is your base method for each.
public static T GetAttribute<T>(this Enum value) where T : Attribute
{
var type = value.GetType();
var memberInfo = type.GetMember(value.ToString());
var attributes = memberInfo[0].GetCustomAttributes(typeof(T), false);
// check if no attributes have been specified.
if (((Array)attributes).Length > 0)
{
return (T)attributes[0];
}
else
{
return null;
}
}
// This method creates a specific call to the above method, requesting the
// Description MetaData attribute.
public static string ToName(this Enum value)
{
var attribute = value.GetAttribute<DescriptionAttribute>();
return attribute == null ? value.ToString() : attribute.Description;
}
/// <summary>
/// Find the enum from the description attribute.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="desc"></param>
/// <returns></returns>
public static T FromName<T>(this string desc) where T : struct
{
string attr;
Boolean found = false;
T result = (T)Enum.GetValues(typeof(T)).GetValue(0);
foreach (object enumVal in Enum.GetValues(typeof(T)))
{
attr = ((Enum)enumVal).ToName();
if (attr == desc)
{
result = (T)enumVal;
found = true;
break;
}
}
if (!found)
{
throw new Exception();
}
return result;
}
}
typeof (PharmacyConfigurationKeys).GetFields()
.Where(x => x.GetCustomAttributes(false).Any(y => typeof(DescriptionAttribute) == y.GetType()))
.Select(x => ((DescriptionAttribute)x.GetCustomAttributes(false)[0]).Description);
public static TAttribute GetEnumAttribute<TAttribute>(this Enum enumVal) where TAttribute : Attribute
{
var memberInfo = enumVal.GetType().GetMember(enumVal.ToString());
return memberInfo[0].GetCustomAttributes(typeof(TAttribute), false).OfType<TAttribute>().FirstOrDefault();
}
public static string GetEnumDescription(this Enum enumValue) => enumValue.GetEnumAttribute<DescriptionAttribute>()?.Description ?? enumValue.ToString();
public static class EnumHelper
{
/// <summary>
/// Gets an attribute on an enum field value
/// </summary>
/// <typeparam name="T">The type of the attribute you want to retrieve</typeparam>
/// <param name="enumVal">The enum value</param>
/// <returns>The attribute of type T that exists on the enum value</returns>
/// <example>string desc = myEnumVariable.GetAttributeOfType<DescriptionAttribute>().Description;</example>
public static T GetAttributeOfType<T>(this Enum enumVal) where T : System.Attribute
{
var type = enumVal.GetType();
var memInfo = type.GetMember(enumVal.ToString());
IEnumerable<Attribute> attributes = memInfo[0].GetCustomAttributes(typeof(T), false);
return (T)attributes?.ToArray()[0];
}
}
public static class EnumerationExtension
{
public static string Description( this Enum value )
{
// get attributes
var field = value.GetType().GetField( value.ToString() );
var attributes = field.GetCustomAttributes( typeof( DescriptionAttribute ), false );
// return description
return attributes.Any() ? ( (DescriptionAttribute)attributes.ElementAt( 0 ) ).Description : "Description Not Found";
}
}
public static class EnumerationExtension
{
public static string Description( this Enum value )
{
// get attributes
var field = value.GetType().GetField( value.ToString() );
var attributes = field.GetCustomAttributes( false );
// Description is in a hidden Attribute class called DisplayAttribute
// Not to be confused with DisplayNameAttribute
dynamic displayAttribute = null;
if (attributes.Any())
{
displayAttribute = attributes.ElementAt( 0 );
}
// return description
return displayAttribute?.Description ?? "Description Not Found";
}
}
public enum ExportTypes
{
[Display( Name = "csv", Description = "text/csv" )]
CSV = 0
}
var myDescription = myEnum.Description();
public enum DataFilters
{
[Display(Name= "Equals")]
Equals = 1,// Display Name and Enum Name are same
[Display(Name= "Does Not Equal")]
DoesNotEqual = 2, // Display Name and Enum Name are different
}
public static string GetDisplayName(this Enum enumValue)
{
var enumMember = enumValue.GetType().GetMember(enumValue.ToString()).First();
return enumMember.GetCustomAttribute<DisplayAttribute>() != null ? enumMember.GetCustomAttribute<DisplayAttribute>().Name : enumMember.Name;
}
public static class AttributeExtensions
{
#region Methods
public static T GetAttribute<T>(this Enum enumValue) where T : Attribute
{
var type = enumValue.GetType();
var memberInfo = type.GetMember(enumValue.ToString());
var member = memberInfo.FirstOrDefault(m => m.DeclaringType == type);
var attribute = Attribute.GetCustomAttribute(member, typeof(T), false);
return attribute is T ? (T)attribute : null;
}
#endregion
}
List<SelectListItem> selectListItems = new List<SelectListItem>();
foreach (var item in typeof(PaymentTerm).GetEnumValues())
{
var type = item.GetType();
var name = type.GetField(item.ToString()).GetCustomAttributesData().FirstOrDefault()?.NamedArguments.FirstOrDefault().TypedValue.Value.ToString();
selectListItems.Add(new SelectListItem(name, type.Name));
}
public enum YourEnum
{
[Display(Name = "Suryoye means Arameans")]
SURYOYE = 0,
[Display(Name = "Oromoye means Syriacs")]
OROMOYE = 1,
}
@using Enumerations
foreach (var name in Html.GetEnumSelectList(typeof(YourEnum)))
{
<h1>@name.Text</h1>
}
public static class AdvancedEnumExtensions
{
/// <summary>
/// Gets the custom attribute <typeparamref name="T"/> for the enum constant, if such a constant is defined and has such an attribute; otherwise null.
/// </summary>
public static T GetCustomAttribute<T>(this Enum value) where T : Attribute
{
return GetField(value)?.GetCustomAttribute<T>(inherit: false);
}
/// <summary>
/// Gets the FieldInfo for the enum constant, if such a constant is defined; otherwise null.
/// </summary>
public static FieldInfo GetField(this Enum value)
{
ulong u64 = ToUInt64(value);
return value
.GetType()
.GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static)
.Where(f => ToUInt64(f.GetRawConstantValue()) == u64)
.FirstOrDefault();
}
/// <summary>
/// Checks if an enum constant is defined for this enum value
/// </summary>
public static bool IsDefined(this Enum value)
{
return GetField(value) != null;
}
/// <summary>
/// Converts the enum value to UInt64
/// </summary>
public static ulong ToUInt64(this Enum value) => ToUInt64((object)value);
private static ulong ToUInt64(object value)
{
switch (Convert.GetTypeCode(value))
{
case TypeCode.SByte:
case TypeCode.Int16:
case TypeCode.Int32:
case TypeCode.Int64:
return unchecked((ulong)Convert.ToInt64(value, CultureInfo.InvariantCulture));
case TypeCode.Byte:
case TypeCode.UInt16:
case TypeCode.UInt32:
case TypeCode.UInt64:
case TypeCode.Char:
case TypeCode.Boolean:
return Convert.ToUInt64(value, CultureInfo.InvariantCulture);
default: throw new InvalidOperationException("UnknownEnumType");
}
}
}
public static string GetDescription(this Enum value) => value.GetType().GetMember(value.ToString()).First().GetCustomAttribute<DescriptionAttribute>() is DescriptionAttribute attribute ? attribute.Description : string.Empty;
using System;
using System.ComponentModel;
using System.Linq;
using System.Reflection;
public static class EnumExtensions
{
// get description from enum:
public static string GetDescription(this Enum value)
{
return value.GetType().
GetMember(value.ToString()).
First().
GetCustomAttribute<DescriptionAttribute>() is DescriptionAttribute attribute
? attribute.Description
: throw new Exception($"Enum member '{value.GetType()}.{value}' doesn't have a [DescriptionAttribute]!");
}
// get enum from description:
public static T GetEnum<T>(this string description) where T : Enum
{
foreach (FieldInfo fieldInfo in typeof(T).GetFields())
{
if (fieldInfo.GetCustomAttribute<DescriptionAttribute>() is DescriptionAttribute attribute && attribute.Description == description)
return (T)fieldInfo.GetRawConstantValue();
}
throw new Exception($"Enum '{typeof(T)}' doesn't have a member with a [DescriptionAttribute('{description}')]!");
}
}
string GetEnumDiscription(Enum EnumValue)
{
var type = EnumValue.GetType();
var memInfo = type.GetMember(EnumValue.ToString());
var attributes = memInfo[0].GetCustomAttributes(typeof(DescriptionAttribute), false);
return (attributes.Length > 0) ? ((DescriptionAttribute)attributes[0]).Description : null;
}