C# enum contains value

Why not use

Enum.IsDefined(typeof(myEnum), value);

BTW it’s nice to create generic Enum<T> class, which wraps around calls to Enum (actually I wonder why something like this was not added to Framework 2.0 or later):

public static class Enum<T>
{
    public static bool IsDefined(string name)
    {
        return Enum.IsDefined(typeof(T), name);
    }

    public static bool IsDefined(T value)
    {
        return Enum.IsDefined(typeof(T), value);
    }

    public static IEnumerable<T> GetValues()
    {
        return Enum.GetValues(typeof(T)).Cast<T>();
    }
    // etc
}

This allows to avoid all this typeof stuff and use strongly-typed values:

Enum<StringSplitOptions>.IsDefined("None")