/// <summary>
/// Method called by proxy interceptor delegate to provide lazy loading behavior for navigation properties.
/// </summary>
/// <typeparam name="TItem">property type</typeparam>
/// <param name="propertyValue">The property value whose associated relationship is to be loaded.</param>
/// <param name="relationshipName">String name of the relationship.</param>
/// <param name="targetRoleName">String name of the related end to be loaded for the relationship specified by <paramref name="relationshipName"/>.</param>
/// <param name="wrapperObject">Entity wrapper object used to retrieve RelationshipManager for the proxied entity.</param>
/// <returns>
/// True if the value instance was mutated and can be returned
/// False if the class should refetch the value because the instance has changed
/// </returns>
private static bool LoadProperty <TItem>(TItem propertyValue, string relationshipName, string targetRoleName, bool mustBeNull, object wrapperObject) where TItem : class
{
// Only attempt to load collection if:
//
// 1. Collection is non-null.
// 2. ObjectContext.ContextOptions.LazyLoadingEnabled is true
// 3. A non-null RelationshipManager can be retrieved (this is asserted).
// 4. The EntityCollection is not already loaded.
Debug.Assert(wrapperObject == null || wrapperObject is IEntityWrapper, "wrapperObject must be an IEntityWrapper");
IEntityWrapper wrapper = (IEntityWrapper)wrapperObject; // We want an exception if the cast fails.
if (wrapper != null && wrapper.Context != null)
{
RelationshipManager relationshipManager = wrapper.RelationshipManager;
Debug.Assert(relationshipManager != null, "relationshipManager should be non-null");
if (relationshipManager != null && (!mustBeNull || propertyValue == null))
{
RelatedEnd relatedEnd = relationshipManager.GetRelatedEndInternal(relationshipName, targetRoleName);
relatedEnd.DeferredLoad();
}
}
return(propertyValue != null);
}
private static bool LoadProperty <TItem>(
TItem propertyValue,
string relationshipName,
string targetRoleName,
bool mustBeNull,
object wrapperObject)
where TItem : class
{
IEntityWrapper entityWrapper = (IEntityWrapper)wrapperObject;
if (entityWrapper != null && entityWrapper.Context != null)
{
RelationshipManager relationshipManager = entityWrapper.RelationshipManager;
if (relationshipManager != null && (!mustBeNull || (object)propertyValue == null))
{
relationshipManager.GetRelatedEndInternal(relationshipName, targetRoleName).DeferredLoad();
}
}
return((object)propertyValue != null);
}
//"doFixup" equals to False is called from EntityCollection & Ref code only
internal void Delete(bool doFixup)
{
ValidateState();
if (doFixup)
{
if (State != EntityState.Deleted) //for deleted ObjectStateEntry its a no-op
{
//Find two ends of the relationship
var entry1 = _cache.GetEntityEntry((EntityKey)GetCurrentRelationValue(0));
var wrappedEntity1 = entry1.WrappedEntity;
var entry2 = _cache.GetEntityEntry((EntityKey)GetCurrentRelationValue(1));
var wrappedEntity2 = entry2.WrappedEntity;
// If one end of the relationship is a KeyEntry, entity1 or entity2 is null.
// It is not possible that both ends of relationship are KeyEntries.
if (wrappedEntity1.Entity != null &&
wrappedEntity2.Entity != null)
{
// Obtain the ro role name and relationship name
// We don't create a full NavigationRelationship here because that would require looking up
// additional information like property names that we don't need.
var endMembers = _relationshipWrapper.AssociationEndMembers;
var toRole = endMembers[1].Name;
var relationshipName = ((AssociationSet)_entitySet).ElementType.FullName;
wrappedEntity1.RelationshipManager.RemoveEntity(toRole, relationshipName, wrappedEntity2);
}
else
{
// One end of relationship is a KeyEntry, figure out which one is the real entity and get its RelationshipManager
// so we can update the DetachedEntityKey on the EntityReference associated with this relationship
EntityKey targetKey = null;
RelationshipManager relationshipManager = null;
if (wrappedEntity1.Entity == null)
{
targetKey = entry1.EntityKey;
relationshipManager = wrappedEntity2.RelationshipManager;
}
else
{
targetKey = entry2.EntityKey;
relationshipManager = wrappedEntity1.RelationshipManager;
}
Debug.Assert(relationshipManager != null, "Entity wrapper returned a null RelationshipManager");
// Clear the detachedEntityKey as well. In cases where we have to fix up the detachedEntityKey, we will not always be able to detect
// if we have *only* a Deleted relationship for a given entity/relationship/role, so clearing this here will ensure that
// even if no other relationships are added, the key value will still be correct and we won't accidentally pick up an old value.
// devnote: Since we know the target end of this relationship is a key entry, it has to be a reference, so just cast
var targetMember = RelationshipWrapper.GetAssociationEndMember(targetKey);
var entityReference =
(EntityReference)
relationshipManager.GetRelatedEndInternal(targetMember.DeclaringType.FullName, targetMember.Name);
entityReference.DetachedEntityKey = null;
// Now update the state
if (State == EntityState.Added)
{
// Remove key entry if necessary
DeleteUnnecessaryKeyEntries();
// Remove relationship entry
// devnote: Using this method instead of just changing the state because the entry
// may have already been detached along with the key entry above. However,
// if there were other relationships using the key, it would not have been deleted.
DetachRelationshipEntry();
}
else
{
// Non-added entries should be deleted
_cache.ChangeState(this, State, EntityState.Deleted);
State = EntityState.Deleted;
}
}
}
}
else
{
switch (State)
{
case EntityState.Added:
// Remove key entry if necessary
DeleteUnnecessaryKeyEntries();
// Remove relationship entry
// devnote: Using this method instead of just changing the state because the entry
// may have already been detached along with the key entry above. However,
// if there were other relationships using the key, it would not have been deleted.
DetachRelationshipEntry();
break;
case EntityState.Modified:
Debug.Assert(false, "RelationshipEntry cannot be in Modified state");
break;
case EntityState.Unchanged:
_cache.ChangeState(this, EntityState.Unchanged, EntityState.Deleted);
State = EntityState.Deleted;
break;
//case DataRowState.Deleted: no-op
}
}
}
