Use Entity framework I want to include only first children objects and not child of child(sub of sub)

by

A downvote brought this answer back into my attention (thank you). I now see that a big part of it is nonsense.

Sure enough, the reason for the endless loop is relationship fixup. But you can’t stop EF from doing that. Even when using AsNoTracking, EF performs relationship fixup in the objects that are materialized in one query. Thus, your query with Include will result in fully populated navigation properties OffersTBLs and BusinessesTBLs.

The message is simple: if you don’t want these reference loops in your results, you have to project to a view model or DTO class, as in one of the other answers. An alternative, less attractive in my opinion, when serialization is in play, is to configure the serializer to ignore reference loops. Yet another less attractive alternative is to get the objects separately with AsNoTracking and selectively populate navigation properties yourself.

Original answer:

This happens because Entity Framework performs relationship fixup, which is the process that auto-populates navigation properties when the objects that belong there are present in the context. So with a circular references you could drill down navigation properties endlessly even when lazy loading is disabled. The Json serializer does exactly that (but apparently it’s instructed to deal with circular references, so it isn’t trapped in an endless loop).

The trick is to prevent relationship fixup from ever happing. Relationship fixup relies on the context’s ChangeTracker, which caches objects to track their changes and associations. But if there’s nothing to be tracked, there’s nothing to fixup. You can stop tracking by calling AsNoTracking():

db.OffersTBLs.Include(s => s.BusinessesTBLs)
             .AsNoTracking()

If besides that you also disable lazy loading on the context (by setting contextConfiguration.LazyLoadingEnabled = false) you will see that only OffersTBL.BusinessesTBLs are populated in the Json string and that BusinessesTBL.OffersTBLs are empty arrays.

A bonus is that AsNoTracking() increases performance, because the change tracker isn’t busy tracking all objects EF materializes. In fact, you should always use it in a disconnected setting.

More Related Contents:

  1. What’s the difference(s) between .ToList(), .AsEnumerable(), AsQueryable()?
  2. Update relationships when saving changes of EF4 POCO objects
  3. Entity Framework Join 3 Tables
  4. One DbContext per request in ASP.NET MVC (without IOC container)
  5. Why LINQ to Entities does not recognize the method ‘System.String ToString()?
  6. Multiple DB Contexts in the Same DB and Application in EF 6 and Code First Migrations
  7. using stored procedure in entity framework
  8. Convert String to Int in EF 4.0
  9. ASP.NET MVC3 and Entity Framework Code first architecture
  10. Non-static method requires a target
  11. How to include a child object’s child object in Entity Framework 5
  12. Using System.ComponentModel.DataAnnotations with Entity Framework 4.0
  13. Entity Framework 4 / POCO – Where to start? [closed]
  14. Saving Many to Many relationship data on MVC Create view
  15. How to do a Bulk Insert — Linq to Entities
  16. Defining multiple Foreign Key for the Same table in Entity Framework Code First
  17. ‘Microsoft.SqlServer.Types’ version 10 or higher could not be found on Azure
  18. The type initializer for ‘System.Data.Entity.Internal.AppConfig’ threw an exception
  19. Converting flattened hierarchical data from SQL Server into a structured JSON object with C#/Linq
  20. Entity Framework Include OrderBy random generates duplicate data
  21. ASP.NET MVC / EF4 / POCO / Repository – How to Update Relationships?
  22. keyword not supported data source
  23. Entity Framework 4 Single() vs First() vs FirstOrDefault()
  24. Model backing a DB Context has changed; Consider Code First Migrations
  25. Incompatible Data Reader Exception From EF Mapped Objects
  26. The conversion of a datetime2 data type to a datetime data type resulted in an out-of-range value
  27. The type or namespace name ‘DbContext’ could not be found [closed]
  28. EntityType ‘Category’ has no key defined. Define the key for this EntityType [duplicate]
  29. Repository Pattern, POCO, and Business Entities
  30. Strongly-Typed ASP.NET MVC with ADO.NET Entity Framework [closed]

Leave a Comment