String to Enum with Description

Question

I am currently implementing an associacion of strings and enums based on this suggestion. That being, I have a Description attribute associated with every enum element. On that page there is also a function which returns the description's string based on the given enum. What I would like to implement now is the reverse function, that is, given an input string lookup the enum with the corresponding description if it exists, returning null otherwise.

I have tried (T) Enum.Parse(typeof(T), "teststring") but it throws an exception.

Answer 1

You have to write your own reverse method. The stock Parse() method obviously doesn't know about your description attributes.

Something like this should work:

public static T GetEnumValueFromDescription<T>(string description)
{
    MemberInfo[] fis = typeof(T).GetFields();

    foreach (var fi in fis)
    {
        DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);

        if (attributes != null && attributes.Length > 0 && attributes[0].Description == description)
            return (T)Enum.Parse(typeof(T), fi.Name);
    }

    throw new Exception("Not found");
}

You'll want to find a better thing to do than throw an exception if the enum value wasn't found, though. :)