Filtering

<input id="multicolumncombobox" />
<script>
$("#multicolumncombobox").kendoMultiColumnComboBox({
   dataSource: [
    { id: 1, name: "Apples" },
    { id: 2, name: "Oranges" }
  ],
  columns: [
    { field: "name" },
    { field: "id" }
  ],
  dataTextField: "name",
  dataValueField: "id",
  filter: "startswith",
  filtering: function(e) {
      //get filter descriptor
      var filter = e.filter;

      // handle the event
  }
});
</script>

<input id="multicolumncombobox" />
<script>
function multicolumncombobox_filtering(e) {
  //get filter descriptor
  var filter = e.filter;

  // handle the event
}
$("#multicolumncombobox").kendoMultiColumnComboBox({
  dataSource: [
    { id: 1, name: "Apples" },
    { id: 2, name: "Oranges" }
  ],
  columns: [
    { field: "name" },
    { field: "id" }
  ],
  dataTextField: "name",
  dataValueField: "id",
  filter: "startswith"
});
var multicolumncombobox = $("#multicolumncombobox").data("kendoMultiColumnComboBox");
multicolumncombobox.bind("filtering", multicolumncombobox_filtering);
</script>

<input id="multicolumncombobox" />
<script>
$("#multicolumncombobox").kendoMultiColumnComboBox({
   dataSource: [
    { id: 1, name: "Apples" },
    { id: 2, name: "Oranges" }
  ],
  columns: [
    { field: "name" },
    { field: "id" }
  ],
  dataTextField: "name",
  dataValueField: "id",
  filter: "startswith",
  filtering: function(e) {
      var filter = e.filter;

      if (!filter.value) {
        //prevent filtering if the filter does not value
        e.preventDefault();
      }
  }
});
</script>