Entity framework not loading relationship even when using include

I have this code:

      Category selectedCategory = (from c in DB.Category.Include("SubCategory")
               join a in DB.Accessory on c.AccCatUID equals a.Category.AccCatUID
               where a.AccUID == currentAccessory.AccUID
               select c).FirstOrDefault();

It works fine, selectedCategory gets populated as expected. BUT selectedCategory has a child table 'SubCategory' which does not get loaded even though there is the 开发者_JAVA百科include there. It is not loaded until I do this:

            selectedCategory.SubCategory.Load();

Why do I have to call load explicitly in order to load the child table?

EDIT: Using .net 3.5 VS2008

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The include is being dropped because it is associated with the first ObjectQuery and not the result set that is coming back.

I think you just need to rework your query? Unless I am missing something you really want the below, i didn't see anywhere you use the accessory join.

        Category selectedCategory = (
             from c in DB.Category.Include("SubCategory")
                where c.AccCatUID == currentAccessory.AccUID
             select c
         ).FirstOrDefault();

or from the otherside

          var fromAccessoryCategory  = 
          (from a in DB.Accessory.Include("Category.SubCategory") 
             where a.AccUID == currentAccessory.AccUID
           select a.Category).FirstOrDefault();