Enum usage

var foo = Importance.Critical.GetDisplayName();
Assert.Equal("Critical", foo);

var dic = EnumHelper.ToDictionary(typeof(Importance));
Assert.Equal(5, dic.Count);

Enum

enum Importance
{
    None,
    Trivial,
    Regular,
    Important,
    Critical
};

EnumHelper

public static class EnumHelper
{
public static IDictionary<Enum, string> ToDictionary(Type type)
{
if (type == null)
{
throw new ArgumentNullException(nameof(type));
}

var dics = new Dictionary<Enum, string>();
var enumValues = Enum.GetValues(type);

foreach (Enum value in enumValues)
{
dics.Add(value, GetDisplayName(value));
}

return dics;
}

public static string GetDisplayName(this Enum value)
{
if (value == null)
{
throw new ArgumentNullException(nameof(value));
}

var displayName = value.ToString();
var fieldInfo = value.GetType().GetField(displayName);
var attributes = (DisplayAttribute[])fieldInfo.GetCustomAttributes(typeof(DisplayAttribute), false);

if (attributes.Length > 0)
{
displayName = attributes[0].Description;
}

return displayName;
}
}