// -------
// Methods
// -------
/// <summary>
/// Loads the related entity or entities into the local related end using the supplied MergeOption.
/// </summary>
public override void Load(MergeOption mergeOption)
{
CheckOwnerNull();
// Validate that the Load is possible
bool hasResults;
ObjectQuery <TEntity> sourceQuery = ValidateLoad <TEntity>(mergeOption, "EntityReference", out hasResults);
_suppressEvents = true; // we do not want any event during the bulk operation
try
{
List <TEntity> refreshedValue = null;
if (hasResults)
{
// Only issue a query if we know it can produce results (in the case of FK, there may not be any
// results).
refreshedValue = new List <TEntity>(GetResults <TEntity>(sourceQuery));
}
if (null == refreshedValue || refreshedValue.Count == 0)
{
if (!((AssociationType)base.RelationMetadata).IsForeignKey && ToEndMember.RelationshipMultiplicity == RelationshipMultiplicity.One)
{
//query returned zero related end; one related end was expected.
throw EntityUtil.LessThanExpectedRelatedEntitiesFound();
}
else if (mergeOption == MergeOption.OverwriteChanges || mergeOption == MergeOption.PreserveChanges)
{
// This entity is not related to anything in this AssociationSet and Role on the server.
// If there is an existing _cachedValue, we may need to clear it out, based on the MergeOption
EntityKey sourceKey = WrappedOwner.EntityKey;
EntityUtil.CheckEntityKeyNull(sourceKey);
ObjectStateManager.RemoveRelationships(ObjectContext, mergeOption, (AssociationSet)RelationshipSet, sourceKey, (AssociationEndMember)FromEndProperty);
}
// else this is NoTracking or AppendOnly, and no entity was retrieved by the Load, so there's nothing extra to do
// Since we have no value and are not doing a merge, the last step is to set IsLoaded to true
_isLoaded = true;
}
else if (refreshedValue.Count == 1)
{
Merge <TEntity>(refreshedValue, mergeOption, true /*setIsLoaded*/);
}
else
{
// More than 1 result, which is non-recoverable data inconsistency
throw EntityUtil.MoreThanExpectedRelatedEntitiesFound();
}
}
finally
{
_suppressEvents = false;
}
// fire the AssociationChange with Refresh
OnAssociationChanged(CollectionChangeAction.Refresh, null);
}