Hi,
For example i deleted 1 node in flowchart,
how can i get the link between before and after deleted node automatically.
When the user deletes a Node by selecting it and invoking the Delete command, CommandHandler.deleteSelection will automatically delete all Links that connect with that Node.
If you want to delete a Node programmatically, call Diagram.remove, which will also remove connected Links. As always, remember to wrap all of the modifying code in a transaction.