CODEWITHSUNDEEP
c#entity-framework
Álvaro García
Álvaro García

Reputation: 19396

entity framework 4: where is my load method and IsLoaded property?

I am using EF4, and I using the System.Data.Entity dll in my class. However, I can't see the load method of my navigation property of my entity.

How can I access to this method?

What I am doing is create e 4.0 project of .NET, create my edmx from a database, right click in the model edmx and I generate a DBContext.

However, I can access to the local property of my context, that I think that is a feature of EF4.

Thanks. Daimroc.

Upvotes: 3

Views: 3382

Answers (2)

Richard Deeming
Richard Deeming

Reputation: 31248

For the DbContext approach, the IsLoaded property and Load method have been moved:

context.Entry(yourEntity)
   .Collection(entity => entity.NavigationProperty)
   .IsLoaded;

context.Entry(yourEntity)
   .Collection(entity => entity.NavigationProperty)
   .Load();

Upvotes: 12

John Nicholas
John Nicholas

Reputation: 4836

When you write the query (all this also works with lambda syntax as well btw)

From a in context.EntitySet.Include("Navigation Property NAme")
select a

and all will be there ;) .. or more to the point the navigation properties will be populated.

can be wierd with lots of joins though

you can also

From a in context.EntitySet.Include("Navigation1.Navigation2.Navigation2")
                           .Include("SomeOtherNavigation")
    select a

where navigation1 and SomeOtherNavigation are navigation properties on the entity set

Failing that you can turn on lazy loading in the context. But its evil imo. Also it doesnt really scale well when you go for an SOA approach as you need to include prior to knowing about the lazy load in your repository.

Ie you run the query in your repository, send stuff over the service and then want the navigation properties in the front end ... by which time its too late to lazy load ... EG you are using a wcf service that doesn't use data services.

Important to note that you ahve to use Include on the EntitySet, it is not on an IQueryable<>.

A real example:

   var csg = from ucsg in c.UserCarShareGroups.Include("UserCarShareGroups.User.UserVehicles")
                      where ucsg.User.UserName.ToLower() == userName.ToLower()
                      && ucsg.CarShareGroup.Carpark.Name.ToLower().Equals(carparkName.ToLower())
                      && ucsg.DeletedBy == null
                      select ucsg.CarShareGroup;

(the database has case sensitive collation for some reason)

An alternate approach (and maybe more relevant is here) Entity Framework - Trouble with .Load()

However I like doing it the way I said because it is explicit and I know exactly what is being pulled out. Especially when dealing with large datasets.

An answer to a question that combines my concerns with Load() is here: Entity Framework 4 load and include combine

Upvotes: 0

Related Questions