This sample illustrates how to apply and visualize task constraints in a Gantt Chart. Task constraints define specific scheduling rules that determine when a task can start or finish, based on project requirements or dependencies.
In Gantt Chart, task constraints define the rules that limit a tasks start or end date based on project scheduling needs. The following constraint types are supported: As Soon As Possible - Task starts as early as possible. Default for auto-scheduled tasks. As Late As Possible - Task finishes as late as possible without delaying dependent tasks. Must Start On - Task must start on the specified date. Must Finish On - Task must finish on the specified date. Start No Earlier Than - Task cannot start before the specified date. Start No Later Than - Task must start on or before the specified date. Finish No Earlier Than - Task cannot finish before the specified date. Finish No Later Than - Task must finish on or before the specified date. You can assign constraints to a task using the taskFields.constraintType and taskFields.constraintDate properties. Constraints can also be updated interactively through the task edit dialog. Handling constraint violation popup: To control or suppress the constraint violation dialog, handle the actionBegin event with requestType as validateTaskViolation. Use args.validateMode to specify how to respond to constraint conflicts. Available properties include: respectMustStartOn respectMustFinishOn respectStartNoLaterThan respectFinishNoLaterThan These options are false by default, which means the violation popup appears. To suppress the popup and cancel conflicting changes silently, set the relevant flag(s) to true. More information on the Essential® JS2 Gantt Chart can be found in this documentation section.