ChangeTracker.TrackGraph Method

Definition

Namespace:

Microsoft.EntityFrameworkCore.ChangeTracking

Assembly:

Microsoft.EntityFrameworkCore.dll

Package:

Microsoft.EntityFrameworkCore v8.0.0

Overloads

TrackGraph(Object, Action<EntityEntryGraphNode>)	Begins tracking an entity and any entities that are reachable by traversing its navigation properties. Traversal is recursive so the navigation properties of any discovered entities will also be scanned. The specified callback is called for each discovered entity and must set the State that each entity should be tracked in. If no state is set, the entity remains untracked.
TrackGraph<TState>(Object, TState, Func<EntityEntryGraphNode<TState>,Boolean>)	Begins tracking an entity and any entities that are reachable by traversing its navigation properties. Traversal is recursive so the navigation properties of any discovered entities will also be scanned. The specified callback is called for each discovered entity and must set the State that each entity should be tracked in. If no state is set, the entity remains untracked.

TrackGraph(Object, Action<EntityEntryGraphNode>)

Begins tracking an entity and any entities that are reachable by traversing its navigation properties. Traversal is recursive so the navigation properties of any discovered entities will also be scanned. The specified callback is called for each discovered entity and must set the State that each entity should be tracked in. If no state is set, the entity remains untracked.

public virtual void TrackGraph (object rootEntity, Action<Microsoft.EntityFrameworkCore.ChangeTracking.EntityEntryGraphNode> callback);

abstract member TrackGraph : obj * Action<Microsoft.EntityFrameworkCore.ChangeTracking.EntityEntryGraphNode> -> unit
override this.TrackGraph : obj * Action<Microsoft.EntityFrameworkCore.ChangeTracking.EntityEntryGraphNode> -> unit

Public Overridable Sub TrackGraph (rootEntity As Object, callback As Action(Of EntityEntryGraphNode))

Parameters

rootEntity

Object

The entity to begin traversal from.

callback

Action<EntityEntryGraphNode>

An action to configure the change tracking information for each entity. For the entity to begin being tracked, the State must be set.

Remarks

This method is designed for use in disconnected scenarios where entities are retrieved using one instance of the context and then changes are saved using a different instance of the context. An example of this is a web service where one service call retrieves entities from the database and another service call persists any changes to the entities. Each service call uses a new instance of the context that is disposed when the call is complete.

If an entity is discovered that is already tracked by the context, that entity is not processed (and its navigation properties are not traversed).

See EF Core change tracking for more information and examples.

TrackGraph<TState>(Object, TState, Func<EntityEntryGraphNode<TState>,Boolean>)

Begins tracking an entity and any entities that are reachable by traversing its navigation properties. Traversal is recursive so the navigation properties of any discovered entities will also be scanned. The specified callback is called for each discovered entity and must set the State that each entity should be tracked in. If no state is set, the entity remains untracked.

public virtual void TrackGraph<TState> (object rootEntity, TState state, Func<Microsoft.EntityFrameworkCore.ChangeTracking.EntityEntryGraphNode<TState>,bool> callback);

abstract member TrackGraph : obj * 'State * Func<Microsoft.EntityFrameworkCore.ChangeTracking.EntityEntryGraphNode<'State>, bool> -> unit
override this.TrackGraph : obj * 'State * Func<Microsoft.EntityFrameworkCore.ChangeTracking.EntityEntryGraphNode<'State>, bool> -> unit

Public Overridable Sub TrackGraph(Of TState) (rootEntity As Object, state As TState, callback As Func(Of EntityEntryGraphNode(Of TState), Boolean))

Type Parameters

TState

The type of the state object.

Parameters

rootEntity

Object

The entity to begin traversal from.

state

TState

An arbitrary state object passed to the callback.

callback

Func<EntityEntryGraphNode<TState>,Boolean>

An delegate to configure the change tracking information for each entity. The second parameter to the callback is the arbitrary state object passed above. Iteration of the graph will not continue down the graph if the callback returns false.

Remarks

This method is designed for use in disconnected scenarios where entities are retrieved using one instance of the context and then changes are saved using a different instance of the context. An example of this is a web service where one service call retrieves entities from the database and another service call persists any changes to the entities. Each service call uses a new instance of the context that is disposed when the call is complete.

Typically traversal of the graph should stop whenever an already tracked entity is encountered or when an entity is reached that should not be tracked. For this typical behavior, use the TrackGraph(Object, Action<EntityEntryGraphNode>) overload. This overload, on the other hand, allows the callback to decide when traversal will end, but the onus is then on the caller to ensure that traversal will not enter an infinite loop.

See EF Core change tracking for more information and examples.