How to read the Value for an EnumMember attribute

Question

public enum Status
    {

        Pending,
        [EnumMember(Value = "In Progress")]
        InProgress,
        Failed,
        Success
    }

string dbValue = "In Progress";
if (dbValue == ValueOf(Status.InProgress)){
//do some thing
}

How do I read the Value of Status.InProgress so I get back "in Progress"?

Answer 1

This is an extension method that works with C# 8 and nullable reference types:

public static string? GetEnumMemberValue<T>(this T value)
    where T : Enum
{
    return typeof(T)
        .GetTypeInfo()
        .DeclaredMembers
        .SingleOrDefault(x => x.Name == value.ToString())
        ?.GetCustomAttribute<EnumMemberAttribute>(false)
        ?.Value;
}

Original Answer:

I've adapted this for .NET Core. Here it is:

public static String GetEnumMemberValue<T>(T value)
    where T : struct, IConvertible
{
    return typeof(T)
        .GetTypeInfo()
        .DeclaredMembers
        .SingleOrDefault(x => x.Name == value.ToString())
        ?.GetCustomAttribute<EnumMemberAttribute>(false)
        ?.Value;
}

Answer 2

Something like this:

public string GetEnumMemberAttrValue(Type enumType, object enumVal)
{
      var memInfo = enumType.GetMember(enumVal.ToString());
      var attr = memInfo[0].GetCustomAttributes(false).OfType<EnumMemberAttribute>().FirstOrDefault();
      if(attr != null)
      {
          return attr.Value;
      }

      return null;
}

Usage:

var enumType = typeof(Status);
var enumVal = Status.InProgress;
var str = GetEnumMemberAttrValue(enumType,enumVal);

Answer 3

Borrowing from Amir's answer, a slightly nicer version is possible using generics as follows:

public string GetEnumMemberAttrValue<T>(T enumVal)
{
    var enumType = typeof(T);
    var memInfo = enumType.GetMember(enumVal.ToString());
    var attr = memInfo.FirstOrDefault()?.GetCustomAttributes(false).OfType<EnumMemberAttribute>().FirstOrDefault();
    if (attr != null)
    {
        return attr.Value;
    }

    return null;
}

Usage as follows:

var enumVal = Status.InProgress;
var str = GetEnumMemberAttrValue(enumVal);

As far as I'm aware T can't be constrained to enum's using a where clause. I would be happy to be corrected though.

Answer 4

Wrapped it in an extension to make it feel more natural:

public static class Extension
{
    public static string ToEnumMemberAttrValue(this Enum @enum)
    {
        var attr = 
            @enum.GetType().GetMember(@enum.ToString()).FirstOrDefault()?.
                GetCustomAttributes(false).OfType<EnumMemberAttribute>().
                FirstOrDefault();
        if (attr == null)
            return @enum.ToString();
        return attr.Value;
    }
}

Usage:

string dbValue = "In Progress";
if (dbValue == Status.ToEnumMemberAttrValue())){
    //do some thing
}

Answer 5

If you have Newtonsoft in your project, that is what you should do:

to the Enum, you should add the attribute [JsonConverter(typeof(StringEnumConverter))]

and now you can call the JsonConvertor to serialize your value as the member string value.

in your example, it should be like that

[JsonConverter(typeof(StringEnumConverter))]
public enum Status
{

    Pending,
    [EnumMember(Value = "In Progress")]
    InProgress,
    Failed,
    Success
}

string dbValue = "In Progress";
if (dbValue == JsonConvert.SerializeObject(Status.InProgress)){
//do some thing
}

Note as mentioned by @Dinesh in the comment that the string is JSON therefor return with quatos so you can workaround that to get a clean string with strin.Replace method as:

dbValue == JsonConvert.SerializeObject(Status.InProgress).Replace("\"","");

Answer 6

    public static object GetMemberAttr(this Enum enumItem)
    {
        var memInfo = enumItem.GetType().GetMember(enumItem.ToString());
        var attr = memInfo[0].GetCustomAttributes(false);
        return attr == null || attr.Length == 0 ? null :((System.Runtime.Serialization.EnumMemberAttribute) attr[0]).Value;
    }

Usage: {YouEnum}.{EnumItem}.GetMemberAttr() public enum TEST_ENUM { [EnumMember(Value = "1min")] Minute, [EnumMember(Value = "2min")] TwoMinutes, [EnumMember(Value = "3min")] ThreeMinutes, }

public TEST_ENUM t;

? t.TwoMinutes.GetMemberAttr()
2min