CODEWITHSUNDEEP
c#.netlinqentity-framework-4.1
Amir Ismail
Amir Ismail

Reputation: 3883

What is the best way to load all navigation properties and their children in EF 4.1

I am trying to get a List<EntityType>, each item has about 15 navigation properties that I need to load, some of navigations properties have a navingation properties that I need to load too, this is a sample code

class AA
{
  public EntityReference<B> Bobj
  {
     get;
     set;
  }
  public EntityCollection<C> CCollection
  {
     get;
     set;
  }
}
class B
{
  public EntityCollection<X> XCollection
  {
     get;
     set;
  }
}
class C
{
  public EntityReference<Y> YObj
  {
     get;
     set;
  }
}

List<AA> AList = Dbcontext.AAs.Where(a => a.ID==4).ToList();

I want each item in List<AA> has been loaded with its BObj with its XCollection and and all CCollection items with its YObj of each.

I tried to load them using Include and Load but I think there is an elegant way to do that

also I tried to set LazyLoadingEnabled to false but that does't load the full graph I don't know why?

so please I need the best way to load the full graph of my EntityType

I am using Database first approach EF 4.1 and C# 4.0

Upvotes: 2

Views: 527

Answers (2)

StriplingWarrior
StriplingWarrior

Reputation: 156459

Here's a neat trick I've picked up:

List<AA> AList = Dbcontext.AAs.Where(a => a.ID==4)
    .Select(a => new {a, a.Bobj, a.CCollection})
    .ToList().Select(o => o.a).ToList();

Dbcontext.Bs.Where(b => b.A.ID==4)
    .Select(b => new {b, b.XCollection})
    .ToList();
Dbcontext.Cs.Where(c => c.A.ID==4)
    .Select(c => new {c, c.YObj})
    .ToList();

Entity Framework will figure out how these various objects are connected. You'll be making a manageable number of round-trips (3 in this case), and the SQL query results produced will have relatively little repeated data.

Upvotes: 5

Alec
Alec

Reputation: 1706

Turning lazy-loading off would prevent them from loading. Turn lazy-loading on and mark all navigation properties as virtual, this will allow them to be overridden so that dynamic proxies can be created. This will allow lazy-loading to work properly. Explicit loading is also an option (and considered by many to be better coding practice).

Edit: Oh I thought it was code first as well, excuse me. Then, if it helps, since Include returns a query object, you can actually loop through a list of them and add them to themselves to build your query dynamically.

Upvotes: 0

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