Eager loading in EntityFramework with DbContext.Da

问题:

In EF 4, can I do eager loading of navigation properties by writing sql on DbContext.Database.SqlQuery or DbContext.Set<T>().SqlQuery? I don't seem to be getting my navigation properties populated.

Edit

It seems I can do eagerloading with DbContext.Set().SqlQuery, just not DbContext.Database.SqlQuery. Any idea why?

回答1:

DbSet.SqlQuery works differently than Database.SqlQuery. The method on DbSet applies to the given entity set. It has to return entities of the given type and by default the returned entities will be tracked. Database.SqlQuery can return any object (possibly not an entity) and the returned objects are never tracked by the context. You may also want to take a look at msdn to compare both methods:

Database.SqlQuery - http://msdn.microsoft.com/en-us/library/gg679117(v=vs.103).aspx

DbSet.SqlQuery - http://msdn.microsoft.com/en-us/library/system.data.entity.dbset.sqlquery(v=VS.103).aspx