private static bool IsSourceReferenceChanged(ObjectStateEntry entry, EntityReference reference)
{
var relationship = (AssociationSet)reference.RelationshipSet;
var constraint = relationship.ElementType.Constraint;
if (constraint.ToRole.Name == reference.TargetRoleName)
{
throw new InvalidOperationException("Dependant end expected.");
}
return(constraint.ToProperties.Any(property => entry.IsPropertyChanged(property.Name)));
}
public bool IsPropertyChanged(string propertyName)
{
return(_stateEntry.IsPropertyChanged(propertyName));
}
private List <Tuple <string, object, object> > GetForeignKeyLabels(ObjectContext context, ObjectStateEntry oce)
{
List <Tuple <string, object, object> > items = new List <Tuple <string, object, object> >();
//FIND FOREIGN KEYS,GET THOSE FOREIGN KEY ENTITY, GET THEIR ENTITY LABELS
var navigations = ((EntityType)oce.EntitySet.ElementType).DeclaredNavigationProperties;
//INCLUDE THESE ENTITY LABELS IN MODIFIED PROPERTIES, SO THAT IT GETS LOGGED
foreach (var navigation in navigations)
{
var rel = oce.RelationshipManager.GetRelatedEnd(navigation.RelationshipType.FullName, navigation.ToEndMember.Name);
//&& rel.IsLoaded
if (rel != null && rel is EntityReference)
{
var reference = (rel as EntityReference);
//for added, deleted entities, we need to retrieve all the foreign objects
//but for changed entities, we only need to retrieve the foreign objects
//if the foreign key it self has changed on the object
if (oce.State == EntityState.Modified)
{
//check if any of the modified property is part of this foreign key
if (reference.EntityKey.EntityKeyValues.Select(kv => kv.Key).Intersect(oce.GetModifiedProperties().Where(prop => oce.IsPropertyChanged(prop))).Count() <= 0)
{
continue;
}
}
object entity;
//if the object is being deleted, retrieve with a special call to TryGetObjectByKey
if (oce.State == EntityState.Deleted)
{
context.TryGetObjectByKey(oce, rel, out entity);
}
else
{
rel.Load();
entity = reference.GetType().GetProperty("Value").GetValue(reference);
}
object oldEntity;
//IF THE OBJECT IS ADDED OR DETACHED THERE IS NO ORIGINAL VALUES
var gotOldEntity = !(oce.State == EntityState.Added || oce.State == EntityState.Detached || oce.State == EntityState.Deleted);
if (gotOldEntity)
{
//CHECK IF WE CAN GET BACK ORIGINAL VALUES
var originalKeys = reference.EntityKey.EntityKeyValues.Select(kv => new EntityKeyMember(kv.Key, oce.OriginalValues[kv.Key]));
gotOldEntity = context.TryGetObjectByKey(new System.Data.Entity.Core.EntityKey(reference.EntityKey.EntityContainerName + "." + reference.EntityKey.EntitySetName, originalKeys), out oldEntity);
//WRITE ORIGINAL VALUES, ONLY IF WE GOT BACK IT SUCCESSFULLY
entity.GetType().GetProperties().Where(y => y.GetCustomAttributes(true).Any(z => z is EntityLabelAttribute)).ToList().ForEach(r => items.Add(new Tuple <string, object, object>(r.Name, gotOldEntity ? r.GetValue(oldEntity) : "", r.GetValue(entity))));
}
else if (oce.State == EntityState.Deleted)
{
entity.GetType().GetProperties().Where(y => y.GetCustomAttributes(true).Any(z => z is EntityLabelAttribute)).ToList().ForEach(r => items.Add(new Tuple <string, object, object>(r.Name, r.GetValue(entity), "")));
}
else
{
//IF NOT, WRITE EMPTY STRINGS FOR ORIGINAL VALUES
entity.GetType().GetProperties().Where(y => y.GetCustomAttributes(true).Any(z => z is EntityLabelAttribute)).ToList().ForEach(r => items.Add(new Tuple <string, object, object>(r.Name, "", r.GetValue(entity))));
}
}
}
return(items);
}