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onBeforeCellRender not getting called upon update()

Asked by Tom Esh
2 months ago.

I have a onBeforeCellRender routine and when I call scheduler.update(), the onBeforeCellRender is not getting executed. I need it to be executed because I changed one of the conditions that the onBeforeCellRender usings when rendering the cell. How can I get the cells to be re-render?

I am using version 2020.4.4807.tar.gz

Answer posted by Dan Letecky [DayPilot]
2 months ago.

If you execute full update() the onBeforeCellRender will always be called. If you call partial update(), e.g. by specifying events only:

dp.update({events: [ ... ]});

then a cached result of onBeforeCellRender will be used.

There are three ways around this:

1. You can disable the caching using beforeCellRenderCaching (for all cells):

2. You can disabled the caching for specific resources using cellsAutoUpdated property of resources[] array items. See more in the following tutorial:

3. You can manually invalidate the cache for selected cells before calling the partial update():

Comment posted by Tom Esh
2 months ago.

I am doing the following:
scheduler: DayPilot.Scheduler = new DayPilot.Scheduler("scheduler");

refresh() {
/* update the events */

this.scheduler.cells.all().invalidate(); // added
this.scheduler.beforeCellRenderCaching = false; // added
and the onBeforeCellRender doesn't get called. Am I doing something wrong?

I need to call the onBeforeCellRender because I need to disable all the cells before the current time.
Is there a better way to disable all the cells before the current time than doing it onBeforeCellRender?

Comment posted by Dan Letecky [DayPilot]
2 months ago.

You might want to check the logic in onBeforeCellRender. The following seems to be working fine in the console:

dp.onBeforeCellRender = function(args) { 
  if (args.cell.start < { = true;

If it still doesn't help, could you please post an example that reproduces the issue? You can generate a blank project at

Comment posted by Tom Esh
2 months ago.

I found a fix.

I was using the following to instantiate a Scheduler instance:

     scheduler: DayPilot.Scheduler = new DayPilot.Scheduler("scheduler");

and the following in the html file:

     <daypilot-scheduler id="scheduler" [(config)]="config" [(events)]="reservations"></daypilot-scheduler>

If I change it to be:

    @ViewChild('scheduler', {static: false})
    scheduler: DayPilotSchedulerComponent;


   <daypilot-scheduler [(config)]="config" [(events)]="reservations" #scheduler></daypilot-scheduler>

and change all the "scheduler" references to be "scheduler.control"
Then the onBeforeCellRenderer gets called on the update() call.

Why doesn't it work when created with:

     scheduler: DayPilot.Scheduler = new DayPilot.Scheduler("scheduler");
Comment posted by Dan Letecky [DayPilot]
2 months ago.

When you add <daypilot-scheduler> to the HTML template Angular will create a placeholder div and a new DayPilot.Scheduler instance which is accessible as DayPilotSchedulerComponent.control. If you create another DayPilot.Scheduler instance it will not get you access to the first instance and its configuration.

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