Question

This is my first attempt at understanding Linq to Entity coming from Net Tiers. Struggling with it but not understanding some of the logic behind it… for instance.
When do I use:

Entity.EntitySet.Load()

and

context.Entity.Include("EntitySet").SingleOrDefault()

Also why does Include take a string and not an enum or sorts?

Answer 1

In EF you have the concepts of Lazy loading and Eager loading.

• Lazy loading means you load the data the moment you need it. This is done trough the Load() method call.
• Eager loading means you already know upfront that you will need some data so you load it in the initial query trough Include(string).

Al tough Include takes a string this doesn’t mean you can’t extend this!

T4 is a nice thing. In a project I’ve worked on we created an EntityProperty class that contained static properties for all the Navigational properties on an entity. This way you would at least get a compile error if a property name changes.

If you really want to go one step further you could build a Include method that takes a Lambda and then rearrange the Expression tree before executing it to the QueryProvider. Then you would have nice static typing.