Duplicate predecessor Task

Gantt
#1

Hi,

How can we prevent the scenario of duplicate predecessor Tasks to the same successor task in the gantt (gantt 4.1.2).

See image below where “Resource Task” has both a F-S & F-F relationship with “New Task 2”

Invalid relationship.png1037×87 11.6 KB

The same setup is not allowed in Ms Project with the error displayed as:

"You cannot link a predecessor task twice to the same successor task)

Thanks
Kevin

#2

Hello,

You need to check source and target tasks’ links. And if these arrays already have common link id - forbid creation the link when “onBeforeLinkAdd” event fires.
Please, see example how to achieve it:
docs.dhtmlx.com/gantt/snippet/437d01cf

docs.dhtmlx.com/gantt/desktop__ … tions.html
docs.dhtmlx.com/gantt/api__gant … event.html