C# enum contains value

Question

I have an enum

enum myEnum2 { ab, st, top, under, below}

I would like to write a function to test if a given value is included in myEnum

Answer 1

   public static T ConvertToEnum(this string value)
    {
        if (typeof(T).BaseType != typeof(Enum))
        {
            throw new InvalidCastException("The specified object is not an enum.");
        }
        if (Enum.IsDefined(typeof(T), value.ToUpper()) == false)
        {
            throw new InvalidCastException("The parameter value doesn't exist in the specified enum.");
        }
        return (T)Enum.Parse(typeof(T), value.ToUpper());
    }