Eager loading in ASP.NET MVC 3 (Entity Framework)

Question

I have a simple data structure

• Employee
• Employee has List
• Education has University, Department
• Department and University has Name as string (I mean Dept. and Univ. are also entity)

My question is, how can I eagerly load specific Employee's education list and each education's university and department information in Entity Framework.

In ASP.NET MVC tutorials there is a query like:

var viewModel = new InstructorIndexData();
viewModel.Instructors = db.Instructors
    .Include(i => i.OfficeAssignment)
    .Include(i => i.Courses.Select(c => c.Department))
    .OrderBy(i => i.LastName);

But my include takes only string parameter (with using System.Linq )

How can I solve this problem?

Thank you...

Answer 1

不是在System.Linq中，而是在System.Data.Entity中（因此使用System.Data.Entity），并且存在于EF 4.1中，但是我必须承认我不知道它出现在哪个版本中。

Answer 2

That snippet is for a new version of EF I thin. What 4.x version are you using?

You should be able to use the name(s) of the Navigation properties:

viewModel.Instructors = db.Instructors
    .Include("OfficeAssignment")
    .Include("Courses.Department")   // not so sure about this one
    .OrderBy(i => i.LastName);