CODEWITHSUNDEEP
entity-framework
Deckard
Deckard

Reputation: 111

Does entity framework lazy loading works automatically when I use virtual?

I was wondering does lazy loading just works when I use virtual or I have to explicitly set it to true, like so:

DbContext.ContextOptions.LazyLoadingEnabled = true;

Upvotes: 0

Views: 574

Answers (3)

ocuenca
ocuenca

Reputation: 39326

The true is there are other requirements you must meet if you want to enable lazy loading and to have Entity Framework track changes in your classes as the changes occur. You can find these requirements in this link:

For either of these proxies to be created:

  • A custom data class must be declared with public access.

  • A custom data class must not be sealed (NotInheritable in Visual Basic)

  • A custom data class must not be abstract (MustInherit in Visual Basic).

  • A custom data class must have a public or protected constructor that does not have parameters. Use a protected constructor without parameters if you want the Create method to be used to create a proxy for the POCO entity. Calling the Create method does not guarantee the creation of the proxy: the POCO class must follow the other requirements that are described in this topic.

  • The class cannot implement the IEntityWithChangeTracker or IEntityWithRelationships interfaces because the proxy classes implement these interfaces.

    The ProxyCreationEnabled option must be set to true.

For lazy loading proxies:

  • Each navigation property must be declared as public, virtual (Overridable in Visual Basic), and not sealed (NotOverridable in Visual Basic) get accessor. The navigation property defined in the custom data class must have a corresponding navigation property in
    the conceptual model.

For change tracking proxies:

  • Each property that is mapped to a property of an entity type in the data model must have non-sealed (NotOverridable in Visual Basic), public, and virtual (Overridable in Visual Basic) get and set accessors.
  • A navigation property that represents the "many" end of a relationship must return a type that implements ICollection, where T is the type of the object at the other end of the relationship.
  • If you want the proxy type to be created along with your object, use the Create method on the DBSet<T> when creating a new object, instead of the new operator.

Upvotes: 3

bubi
bubi

Reputation: 6491

By default 

DbContext.ContextOptions.LazyLoadingEnabled

is set to true so if you don't forget virtual and you don't mark class as sealed it works.

Upvotes: 0

Brad Christie
Brad Christie

Reputation: 101604

Entity Framework Loading Related Entities

Lazy loading is the process whereby an entity or collection of entities is automatically loaded from the database the first time that a property referring to the entity/entities is accessed. When using POCO entity types, lazy loading is achieved by creating instances of derived proxy types and then overriding virtual properties to add the loading hook. [...]

To answer your question, as long as it's enabled, yes, virtual navigation properties will be lazy-loaded.

Upvotes: 0

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