If you are disabling server operations of the DataSource you will need to use the view
method instead of the data
method of the DataSource in order to get the data items from the current view (including the sort, filter, etc.
var rowCount = gridService.dataSource.view().length;
As for the navigation, please try to create a dojo
example demonstrating your current implementation, so we could have a better idea of the exact scenario.
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