Hi Mark,
Sorry for the delay in responding you.
Do I need to tell the grid that it's datasource has been updated, so it re-paints itself .It is not required to explicitly update/refresh the grid when underlying datasource has been changed. The underlying datasource(List<>)includes support for change notifications when the list is modified. It does have a ListChanged event which will be fired upon any data changes. If the collection supports changes, it should also support firing a ListChanged event when the collection changes.
Hence when items are added or removed or modified from underlying datasource, the grouping grid will be notified of these changes and will update itself automatically.
Sample referenceIn the sample provided, the grid gets updated automatically when items are added or removed from the underlying datasource.
http://websamples.syncfusion.com/samples/Grouping.Windows/F68611/main.htmYou can also refer the samples that shipped with Essential studio in the below location.
[Install drive]:\Documents and Settings\UserName\My Documents\Syncfusion\EssentialStudio\Version\Windows\Grid.Grouping.Windows\Samples\2.0\CustomCollections
Please let me know if you still face any issues.
Thanks for your patience.
Regards,
Jaya