public void AddParentChildRelationship(ParentChildRelationship parentChildRelationship)
{
if (RelationshipCreatesCycle(parentChildRelationship))
{
throw new ArgumentException($"Adding {parentChildRelationship.Parent.Id}->{parentChildRelationship.Child.Id} relationship would create a circular reference.");
}
ParentChildRelationships.Add(parentChildRelationship); // store in DB
}
private bool AnyDescendantEquals(Entity condition, ParentChildRelationship childToTest, HashSet <int> visitedIds = null)
{
var visited = visitedIds ?? new HashSet <int>();
if (childToTest.Child.Id == condition.Id)
{
return(true);
}
visited.Add(childToTest.Child.Id);
var childrenOfChildToTest = ParentChildRelationships.Where(x => x.Parent.Id == childToTest.Child.Id);
return(childrenOfChildToTest.Any(r => !visited.Contains(r.Child.Id) && AnyDescendantEquals(condition, r, visited)));
}
private bool RelationshipCreatesCycle(ParentChildRelationship parentChildRelationship)
{
return(AnyDescendantEquals(parentChildRelationship.Parent, parentChildRelationship));
}