Hi, 

I wanted to implement RadComboBox combined with checkboxes and load on demand approach.

However, this page explained it is not possible and advised to use RadMultiSelect with Virtualization

https://docs.telerik.com/devtools/aspnet-ajax/controls/combobox/functionality/checkbox-support

I checked the page and demo is explained via web service... 

Is there a demo where it would be explained that when I type e.g. 3 characters some function would be called (e.g. OnItemsRequested) and in the server I would call database and fill the required data ? We don't have web service for providing the data... In code-behind we always access databases.

Thanks,

Peter