Combobox server filtering and virtualization

[Dan]

I have an old application where the user was entering an input a dropdown list (of multiple values concatenated) was displayed and he could filter the list based on the values displayed.

Now we decided to use Combobox since the Autocomplete does not open the dropdown when the autocomplete receives focus. Since the list contains too many values I though I should try also virtualization

@(Html.Kendo().ComboBox()
   .Name("deviceclassselection")
   .HtmlAttributes(new { @class = "form-control s-device-class" })
   .DataSource(dataSource => dataSource.Ajax()
                           .Read(read => read.Action("GetDeviceClasses", "Device").Data("device.getDeviceClassAdditionalData"))
                           .PageSize(40)
                           .Events(events => events.Error("device.dataSourceError")))
   .Template("#= data.Designation # - #= data.Manufacturer # - #= data.Model #")
   .Height(200)
   .Events(events => events.Select("device.deviceClassSelect"))
   .Virtual(v => v.ItemHeight(26).MapValueTo("dataItem"))
   .Deferred()
)

However when I write something in the combobox no event is triggered on the server. If I open the dropdown manually the server is called.

I tried removing the Virtual and the result was the same (Probably it did not worked because I left the Ajax and the PageSize).

[Neli]

Hello Dan,

Could you please enable the serverPaging of the widget. you could take a look of the configuration of the ComboBox in the Virtualization Demo linked here. 
For convenience I am attaching a sample project where the virtualization of the ComboBox is enabled. when the user types in the input field, a request is sent to the remote server.
In addition, I would suggest you to refer to the article regarding virtualization, as it could be helpful. 

Regards,
Neli
Progress Telerik

[Dan]

Hi Neli,

Thank you for responding to me. After some investigation I managed to figure out why it was not working. I forgot to add the Filter(FilterType.Contains) and also the thing you suggested with the ServerOperation(true). After I did this the combobox started to behave as expected.