protected virtual bool CheckLinkValid( NodeType newfromdata, NodeType newtodata, bool ignoreexistinglink, NodeType oldfromdata, NodeType oldtodata )
Parameters
- newfromdata
- a node key identifying the node data from which the link would come
- newtodata
- a node key identify the node data to which the link would go
- ignoreexistinglink
- true if relinking; false if adding a new link
- oldfromdata
- a node key identifying the node data from which the existing link comes
- oldtodata
- a node key identify the node data to which the existing link goes
Return Value
This returns false for links that would break the tree structure of the model's graph,
due to either cycles or multiple "parent"s.
This also returns false for duplicate links, even if they would otherwise be valid.