public enum EmpTypes
{
    [Display(Name = "Service")]
    Service = 0,
    [Display(Name = "Sales")]
    Sales = 1,
    [Display(Name = "Purchase")]
    Purchase = 2,
    [Display(Name = "Office")]
    Office = 3
}

columns.Bound(c => c.EmpTypes).Title("Type")
        .Filterable(filterable => filterable
            .Multi(true)
            .UI(“”).DataSource(s=>s.Read(r=>r.Action(“GetEmpTypes”,”Report”)))
            .ItemTemplate(“typetemplate”));
<script>
 function typetemplate(e)
{
  alert('Test');
}

</script>

Public ActionResult GetEmpTypes()
{
 List<EmpType> emptypes = new List<EmpType>();
emptypes.Add(EmpType.Sales)
emptypes.Add(EmpType.Report)
return Json(emptypes,JsonRequestBehavior.AllowGet);
}

                 onComboBoxDataBound: function (evt) {
                    var widget = evt.sender;
                    if (this.dataSource.total() > 0) {
                        // delete preselection then try to select entry with id -1
                        $('#modComboBox').data('kendoComboBox').input.select();
                        $('#modComboBox').data('kendoComboBox').input.val('');
                        $('#modComboBox').data('kendoComboBox').select(function (data) {
                            return data.id == -1;
                        });
                        // no selection then select first entry
                        if (widget.select() === -1) { // hint I found in stackoverflow
                            $('#modComboBox').data('kendoComboBox').select(0);
                        }
                    }
                },

        col.dataTextField = col.dataTextField ?? "text";
        col.dataValueField = col.dataValueField ?? "value";
        col.dataSource = {
            type: "json",
            transport: {
                read: function (options) {
                    ufn_ApiGetLookup({
                        data: col.source,
                        success: function (d) {
                            options.success(ufn_GetData(d));
                        }
                    });
                }
            }
        }

 @(Html.Kendo().ComboBox()
                            .Name("combo" + item.DataField.ID)
                            .Filter("contains")
                            .DataTextField("DataTextField")
                            .DataValueField("DataTextValue")
                            .Placeholder("Select an item...")
                            .AutoBind(false)
                            .ClearButton(true)
                            .DataSource(source =>
                            {
                                
                                source.Custom()
                                    .ServerFiltering(true)
                                    .ServerPaging(true)
                                    .PageSize(40)
                                    
                                    .Type("aspnetmvc-ajax") //Set this type if you want to use DataSourceRequest and ToDataSourceResult instances
                                    .Transport(transport =>
                                    {

                                        transport.Read(r =>
                                        {

                                            
                                            r.Action("Virtualization_ReadComboEdit3", "Search", new { dataFieldId = item.DataField.ID }).Type(HttpVerbs.Post).Data("getFormData");



                                        });
                                        

                                    })
                                    
                                    .Schema(schema =>
                                    {
                                        schema.Data("Data") //define the [data](https://docs.telerik.com/kendo-ui/api/javascript/data/datasource#configuration-schema.data) option
                                              .Total("Total"); //define the [total](https://docs.telerik.com/kendo-ui/api/javascript/data/datasource#configuration-schema.total) option
                                    });
                            })
                        .HtmlAttributes(new { style = "width:100%;", data_parent_id = (item.DataField.ParentDataFieldID!=null ? item.DataField.ParentDataFieldID.ToString() : ""), data_conditional = item.DataField.IsConditionListener })
                        .FooterTemplate("<b>#: instance.dataSource.total() # items found<b/>")
                        .Events(e =>
                        {
                            e.Select("onSelectCombo");
                            e.Open("onOpenCombo");
                            e.Change("onChangeCombo");



                        })
                        .Virtual(v =>
                        {
                            v.MapValueTo("dataItem");
                            v.ItemHeight(26);
                            v.ValueMapper(e => "function(options) { dropdownMapper(options," + item.DataField.ID + "); }");
                        })
                        .Value(item.DataField.CurrentFieldValueSingle.ToString())
                        .Text(item.DataField.CurrentFieldText)
                            )