This is a follow up from my last post 'Grid state on hierarchical grid' see link:

https://www.infragistics.com/community/forums/f/ignite-ui-for-angular/124279/grid-state-on-hierarchical-grid

So after a long few days i have found the problem.

It turns out that the parentRowId is being cleared before the component is destroyed.

I followed the Hierarchical Grid State persistence example here:

https://www.infragistics.com/products/ignite-ui-angular/angular/components/hierarchicalgrid/state-persistence#demo

and found that this works as expected. I noticed that the saveGridState is called from a subscribed callback from router in ngOnInIt, we have been using ngOnDestroy because this seemed like a logical place and it has been working perfectly well for the last few years for us on the basic igx-grid.

However since trying to apply the same logic to IgxHierarchicalGridComponent the rowIslands child grids get destroyed somewhere before ngOnDestroy,

So if you trace through the code in igniteui-angular.js and method getParentRowId this.childGrids has a zero length array:

Therefore the resulting gridState rowIslands have undefined parentRowID

So when you return back to the component and re-apply the gridState on ngAfterViewInit the rowIslands are ignored.

My questions are: Is this a bug? And is the only way for this to work is to use the router callback in ngOnInIt

Thanks.