Linq To SQL OrderBy，使用枚举时出现问题

I am having some issues with using the OrderBy extension method on a LINQ query when it is operating on an enum type. I have created a regular DataContext using visual studio by simply dragging and dropping everything onto the designer. I have then created seperate entity models, which are simply POCO's, and I have used a repository pattern to fetch the data from my database and map them into my own entity models (or rather, I have a repository pattern, that builds up and IQueryable that'll do all this).I am having some issues with using the OrderBy