Getting attributes of Enum's value

Question

I would like to know if it is possible to get attributes of the enum values and not of the enum itself? For example, suppose I have the following <

Answer 1

Bryan Rowe and AdamCrawford thanks for your answers!

But if somebody need method for get Discription (not extension) you can use it:

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;
        }

Answer 2

This extension method will obtain a string representation of an enum value using its XmlEnumAttribute. If no XmlEnumAttribute is present, it falls back to enum.ToString().

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;
}

Answer 3

This is how I solved it without using custom helpers or extensions with .NET core 3.1.

Class

public enum YourEnum
{
    [Display(Name = "Suryoye means Arameans")]
    SURYOYE = 0,
    [Display(Name = "Oromoye means Syriacs")]
    OROMOYE = 1,
}

Razor

@using Enumerations

foreach (var name in Html.GetEnumSelectList(typeof(YourEnum)))
{
    <h1>@name.Text</h1>
}

Answer 4

Taking advantage of some of the newer C# language features, you can reduce the line count:

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();

Answer 5

In addition to AdamCrawford response, I've further created a more specialized extension methods that feed of it to get the description.

public static string GetAttributeDescription(this Enum enumValue)
{
    var attribute = enumValue.GetAttributeOfType<DescriptionAttribute>();
    return attribute == null ? String.Empty : attribute.Description;
} 

hence, to get the description, you could either use the original extension method as

string desc = myEnumVariable.GetAttributeOfType<DescriptionAttribute>().Description

or you could simply call the the extension method here as:

string desc = myEnumVariable.GetAttributeDescription();

Which should hopefully make your code a bit more readable.

Answer 6

    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             
    }

Now it will produce error in this case 1 "Equals"

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;
    }

so if it is same return enum name rather than display name because enumMember.GetCustomAttribute() gets null if displayname and enum name are same.....