我想知道是否有可能获得枚举值的属性,而不是枚举本身?例如,假设我有以下枚举:

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,产生枚举字符串值及其描述的二元组。

价值很简单:

Array values = System.Enum.GetValues(typeof(FunkyAttributesEnum));
foreach (int value in values)
    Tuple.Value = Enum.GetName(typeof(FunkyAttributesEnum), value);

但我如何获得描述属性的值,以填充Tuple.Desc?如果属性属于枚举本身,我可以想到如何做到这一点,但我不知道如何从枚举的值中获得它。


当前回答

添加我的解决方案的Net Framework和NetCore。

我在我的Net Framework实现中使用了这个:

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";
    }
}

这并不适用于NetCore,所以我修改了它,这样做:

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";
    }
}

枚举的例子:

public enum ExportTypes
{
    [Display( Name = "csv", Description = "text/csv" )]
    CSV = 0
}

使用任何静态添加:

var myDescription = myEnum.Description();

其他回答

这应该能满足你的需要。

try
{
  var enumType = typeof(FunkyAttributesEnum);
  var memberInfos = 
  enumType.GetMember(FunkyAttributesEnum.NameWithoutSpaces1.ToString());
  var enumValueMemberInfo = memberInfos.FirstOrDefault(m => 
  m.DeclaringType == enumType);
  var valueAttributes = 
  enumValueMemberInfo.GetCustomAttributes(typeof(DescriptionAttribute), false);
  var description = ((DescriptionAttribute)valueAttributes[0]).Description;
}
catch
{
    return FunkyAttributesEnum.NameWithoutSpaces1.ToString()
}

从enum中获取字典。

public static IDictionary<string, int> ToDictionary(this Type enumType)
{
    return Enum.GetValues(enumType)
    .Cast<object>()
    .ToDictionary(v => ((Enum)v).ToEnumDescription(), k => (int)k); 
}

现在把它叫做…

var dic = typeof(ActivityType).ToDictionary();

枚举描述Ext方法

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
}

或者,你可以这样做:

Dictionary<FunkyAttributesEnum, string> description = new Dictionary<FunkyAttributesEnum, string>()
    {
      { FunkyAttributesEnum.NameWithoutSpaces1, "Name With Spaces1" },
      { FunkyAttributesEnum.NameWithoutSpaces2, "Name With Spaces2" },
    };

并使用以下语句获取描述:

string s = description[FunkyAttributesEnum.NameWithoutSpaces1];

在我看来,这是一种更有效的方式去做你想要完成的事情,因为不需要思考。

    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             
    }

在这个例子中它会产生错误1 "等于"

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;
    }

如果它是相同的返回enum名称而不是显示名称因为 enumMember.GetCustomAttribute () 如果displayname和enum name相同,则返回null .....

朋友们,如果有帮助的话,我将与你们分享我的解决方案: Custom属性的定义:

    [AttributeUsage(AttributeTargets.Field,AllowMultiple = false)]
public class EnumDisplayName : Attribute
{
    public string Name { get; private set; }
    public EnumDisplayName(string name)
    {
        Name = name;
    }
}

现在因为我需要它在HtmlHelper扩展的HtmlHelper定义内:

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");
    }
}

希望能有所帮助