DropDownList DataSource extension not generates datasource script

[Szymon]

In my project this code

@(Html.Kendo().DropDownListFor(x => x.Event.DisconnectionId)

                               .DataValueField("Id")

                               .DataTextField("Name")

                                          .DataSource(source =>

                                          {

                                              source.Read(read =>

                                              {

                                                  read.Action("_Disconnections", "Event");

                                              })

                                              .ServerFiltering(true);

                                          })

                             )

generates following html

<input id="Event_DisconnectionId" name="Event.DisconnectionId" type="text" value="0" /><script>

   jQuery(function(){jQuery("#Event_DisconnectionId").kendoDropDownList({dataTextField:"Name",dataValueField:"Id"});});

Could not read  "disconnections" data because datasource property (dataSource:{transport:{read:{url:"/Event/_Disconnections" ... etc. ) is not generated. Why? Please help.

[Atanu]

How you are populating the dropdownlist.
You haven't specified what is written inside the _Disconnections controller action.

Please share some more code.

[Szymon]

Solved. I had no default route in routing configuration file and for this action UrlHelper was returning null url. In result dataSource property was not generated. 

In my opinion it is Kendo design error. It should throws exception when url is null. It took me a days...