using System;

using System.ComponentModel;

public class Program

{

    public static void Main()

    {

        const MyEnum expected = MyEnum.Bar;

        var actual = GetValueFromDescription<MyEnum, DescriptionAttribute>("Bar Lorem");

        Console.WriteLine( actual == expected);

    }

    private enum MyEnum{

        [Description("Bar Lorem")]

        Bar,

        [Description("Foo Lorem")]

        Foo

    }

    public static T GetValueFromDescription<T, TAttribute>(string description) where TAttribute : System.Attribute

    {

        var type = typeof(T);

        var descriptionType = typeof(TAttribute);

        if(!type.IsEnum) throw new InvalidOperationException();

        foreach(var field in type.GetFields())

        {

            TAttribute attribute = (TAttribute)Attribute.GetCustomAttribute(field, descriptionType);

            if(attribute != null)

            {

                if(attribute.Description == description) //problem

                    return (T)field.GetValue(null);

            }

            else

            {

                if(field.Name == description)

                    return (T)field.GetValue(null);

            }

        }

        throw new ArgumentException("Not found.", "description");

        // or return default(T);

    }

}