private void InferRelationHistories(ObjectContext ctx)
{
List <RelationWrapper> relations = new List <RelationWrapper>(this.Relations);
// The first time scan for those have corresponding change action recorded.
for (int i = 0; i < relations.Count; i++)
{
RelationWrapper relation = relations[i];
// Look into the relationship from two direction, which could provide a uniform way.
foreach (RelationEndWrapper end in relation.GetRelationEnds())
{
object entityRaw;
if (ctx.TryGetObjectByKey(end.SourceKey, out entityRaw))
{
IWithHistory entity = entityRaw as IWithHistory;
if (entity != null)
{
ChangeEntry change = entity.CollectionChanges.ChangedEntries.Find(x => this.AssertChangeMatch(x, relation, end.TargetAssociationEnd.Name));
// Find out recorded change action matches current relation..
if (change != null)
{
// Remove from list. let the rest of list keep clean as not developed.
relations.Remove(relation);
i--;
HistoryPreparation hp = new HistoryPreparation(change);
// Prepare basic change history.
RawChangeHistory rch = new RawChangeHistory(change.Source,
change.Monitor.PropertyID,
change.Target,
change.Action);
hp.Relations.Add(rch);
// Start prepare extra history.
if (end.TargetAssociationEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many)
{
// This is n to n association.
if (change.Target is IWithHistory)
{
// Whether this EntityType at opposite requires history and has corresponding property in metadata.
EntityPropertyInfo pi = MetadataManager.GetEntityProperty(change.Monitor.PropertyID, true);
if (pi.OppositePropertyReference.GetValueAutoLoaded() != null)
{
RawChangeHistory rch1 = new RawChangeHistory(change.Target,
pi.OppositePropertyReference.GetValueAutoLoaded().ID,
change.Source,
change.Action);
hp.Relations.Add(rch1);
}
}
}
else
{
// This is n to 0..1 association.
if (change.Action == CollectionChangeAction.Add)
{
EntityPropertyInfo pi = MetadataManager.GetEntityProperty(change.Monitor.PropertyID, true);
RelationEndWrapper end1 = null;
// Find out a deleted relation which is possibly occur because of current added one.
RelationWrapper relation1 = relations.Find(x =>
(x.State == EntityState.Deleted) &&
String.Equals(x.Definition.Name, relation.Definition.Name) &&
this.AssertRelationSameTarget(x, relation, EntityState.Deleted, end, out end1));
if (relation1 != null)
{
if (entity.CollectionChanges.ChangedEntries.Find(x => this.AssertChangeMatch(x, relation, end.TargetAssociationEnd.Name)) == null)
{
// No recorded change matches this relation. so it did really occur because of current added one.
if (relations.IndexOf(relation1) <= i)
{
i--;
}
relations.Remove(relation1);
RawChangeHistory rch1 = new RawChangeHistory((EntityObject)ctx.GetObjectByKey(end1.SourceKey), change.Monitor.PropertyID, change.Target, CollectionChangeAction.Remove);
hp.Relations.Add(rch1);
}
}
if ((change.Target is IWithHistory) &&
(pi.OppositePropertyReference.GetValueAutoLoaded() != null))
{
hp.Entities.Add(change.Target);
}
}
}
entity.CollectionChanges.CachedHistories.Add(hp);
}
}
}
}
}
// Second time scan for those relation changes launched by assigning on entity.
for (int i = 0; i < relations.Count; i++)
{
RelationWrapper relation = relations[i];
foreach (RelationEndWrapper end in relation.GetRelationEnds())
{
if (end.TargetAssociationEnd.RelationshipMultiplicity != RelationshipMultiplicity.Many)
{
EntityWrapper er = this.Entities.Find(x => x.Key.Equals(end.SourceKey));
IWithHistory entity = null;
if (er == null)
{
// Normal properties of this entity have not been changed. so it should be added to entity history list.
entity = ctx.GetObjectByKey(end.SourceKey) as IWithHistory;
if (entity != null)
{
this.AddChangedEntity(EntityState.Unchanged, (EntityObject)entity);
}
}
else
{
entity = er.Entity as IWithHistory;
}
// Prepare relation histories.
}
}
}
}
private bool AssertRelationSameTarget(RelationWrapper relation, RelationWrapper targetRelation, EntityState state, RelationEndWrapper targetEnd, out RelationEndWrapper correspondingEnd)
{
correspondingEnd = null;
bool ret = (relation.State == state) &&
String.Equals(relation.Definition.Name, targetRelation.Definition.Name);
foreach (RelationEndWrapper end in relation.GetRelationEnds())
{
ret = String.Equals(end.TargetAssociationEnd.Name, correspondingEnd.TargetAssociationEnd.Name) &&
end.TargetKey.Equals(targetEnd.TargetKey);
if (ret)
{
correspondingEnd = end;
break;
}
}
return(ret);
}