title: Kendo Grid Server side filtering with a array type column
body: <p>I have this kendo grid blinded to my web service. One of the columns has a custom filter with a kendo multiselector array so the client can choose multiple ItemTypes. The grid is displaying data correctly but my costume filters are not working for this particular column. I got this error from the service: <strong>"A binary operator with incompatible types was detected. Found operand types 'Telerik.Sitefinity.DynamicTypes.Model.ClinicFinder.Clinic.ItemType.ItemType' and 'Edm.Int32' for operator kind 'Equal'."</strong></p>
  
  <p>My grid definition</p>
  
  <pre><code>$("#grid").kendoGrid({
  dataSource: {
      type: "odata-v4",
      transport: {
          read: {
              url: function () {                    
                  return "//myservice/api/clinics?$select=Id,Title,Address,ItemType,productsystems&amp;top=20";
              }
          }
      },
      schema: {
          model: {
              fields: {
                  Title: { type: "string" },
                  CountryCode: { type: "string" },
                  Street: { type: "string" },
                  City: { type: "string" },
                  Zip: { type: "string" },
                  ItemType: { type: "" } 
  
  
              }
          }
      },
      serverPaging: true,
      serverFiltering: true,        
      serverSorting: false,
      pageSize: 20
  },
  pageable: true,
  filterable: {
      mode: "row",
      extra: false,
      showOperators: false,
      operators: {
          string: {
              contains: "contains"
          }
      }
  },
  sortable: false,
  columns: [
      { field: "Title", title: "Clinic" },
      { field: "CountryCode", title: "Country" },
      { field: "Street", title: "Address" },
      { field: "City", title: "City"  },
      { field: "Zip", title: "Zip",  filterable: false },       
      { field: "ItemType", title: "Clinic Type", filterable: { multi: true } }
  ],
  rowTemplate: kendo.template($("#template").html())    
  
  });
  </code></pre>
  
  <p>My Filter function</p>
  
  <pre><code>function filterByclinicCategory() {
  var filter = { logic: "or", filters: [] };
  var grid = $('#grid').data('kendoGrid');
  var filterValue = $("#clinicTypeFilter").data("kendoMultiSelect").value();
  var clinicCode = [];
  if (filterValue.length &gt; 0) {
      $.each(filterValue, function (i, v) {
          clinicCode.push(convertClinicTypesInCodes(v));
          filter.filters.push({
              field: "ItemType", operator: "eq", value: clinicCode, logic: "or"
          });
          grid.dataSource.filter(filter);    
      });
  
  } else {
      $("#grid").data("kendoGrid").dataSource.filter({});
  }
  
  
  }
  </code></pre>
  
  <p>ItemType is the column I can´t filter.</p>
  
  <p>My webservice data</p>
  
  <pre><code>{
  "@odata.context": "https://sf-admin-local.medel.com/api/wstest/$metadata#clinics(*)",
  "value": [
  {
  "Id": "896aa08b-2f17-64e6-80bd-ff09000c6e28",
  "LastModified": "2019-05-13T09:28:04Z",
  "PublicationDate": "2018-06-19T14:19:13Z",
  "DateCreated": "2018-06-19T14:19:13Z",
  "UrlName": "??",
  "Email": "",
  "URL": "",
  "Telephone": "",
  "Title": "????????",
  "officeregions": [],
  "salespartnerregions": [],
  "productsystems": [
  "b8ec2a8b-2f17-64e6-80bd-ff09000c6e28",
  "1878cb61-ac79-69d9-867b-ff01007297b6",
  "1b78cb61-ac79-69d9-867b-ff01007297b6",
  "36d8938b-2f17-64e6-80bd-ff09000c6e28"
  ],
  "Area": "",
  "Order": 0,
  "Tags": [],
  "AdditionalInformation": "",
  "ImportID": 1,
  "Featured": false,
  "ItemType": "2",
  "Address": {
  "Id": "d76aa08b-2f17-64e6-80bd-ff09000c6e28",
  "CountryCode": "AT",
  "StateCode": "",
  "City": "????",
  "Zip": "6800",
  "Street": "Carinagasse ?????",
  "Latitude": 47.2311043,
  "Longitude": 9.580079999999953,
  "MapZoomLevel": 8
  }
  }
  ]
  }
  </code></pre>