or
dataSource: { type: "aspnetmvc-ajax", transport: { read: { url: "@Url.Action("_GetEHR", "Performance")", type: "POST", contentType: "application/json", data: //searchOptions() { periodDate: function () { return kendo.toString($("#periodDate").data("kendoDatePicker").value(), "MMM yyyy") } } }, parameterMap: function (options) { return JSON.stringify(options); } }, serverSorting: true, serverFiltering: true, serverPaging: true, pageSize: 50, schema: { model: { fields: { AccountName: { type: "string" }, Month1: { EHR: { type: "number" } }, Month2: { EHR: { type: "number" } }, Month3: { EHR: { type: "number" } }, Month4: { EHR: { type: "number" } }, Month5: { EHR: { type: "number" } }, Month6: { EHR: { type: "number" } }, Month7: { EHR: { type: "number" } }, Month8: { EHR: { type: "number" } }, Month9: { EHR: { type: "number" } }, Month10: { EHR: { type: "number" } }, Month11: { EHR: { type: "number" } }, Month12: { EHR: { type: "number" } } } }, data: function (data) { return data.Data; }, total: function (data) { return data.Total; } },},{"GetDocumentsResult":[{"AnnoEsercizio":2013,"BatchID":636614,"CustomerDocumentTypeID":401,"Data":"\/Date(1366236000000+0200)\/","FileExtension":".jpg","FollowUp":{"Fk_ID_ressol":11,"FollowUp1":"\/Date(1367877600000+0200)\/","FollowUp2":null,"FollowUp3":null,"Id":4,"Note":null},"Frequenza":"MENSILE","Id":4,"Nota":null,"ObjectID":"1","PathBuildingRuleID":9,"Piva":"xdfdff","RagioneSociale":"Kellner","RepositoryRegistrationDate":"\/Date(1358463600000+0100)\/","Stato":"OK"},{"AnnoEsercizio":2013,"BatchID":636614,"CustomerDocumentTypeID":401,"Data":"\/Date(1361142000000+0100)\/","FileExtension":".jpg","FollowUp":null,"Frequenza":"MENSILE","Id":5,"Nota":null,"ObjectID":"2","PathBuildingRuleID":9,"Piva":"xdfdff","RagioneSociale":"Kellner","RepositoryRegistrationDate":"\/Date(1366236000000+0200)\/","Stato":"OK"},{"AnnoEsercizio":2013,"BatchID":636614,"CustomerDocumentTypeID":401,"Data":"\/Date(1363561200000+0100)\/","FileExtension":".jpg","FollowUp":null,"Frequenza":"MENSILE","Id":6,"Nota":null,"ObjectID":"3","PathBuildingRuleID":9,"Piva":"xdfdff","RagioneSociale":"Kellner","RepositoryRegistrationDate":"\/Date(1366236000000+0200)\/","Stato":"OK"},{"AnnoEsercizio":2013,"BatchID":636614,"CustomerDocumentTypeID":401,"Data":"\/Date(1366236000000+0200)\/","FileExtension":".jpg","FollowUp":null,"Frequenza":"MENSILE","Id":7,"Nota":null,"ObjectID":"4","PathBuildingRuleID":9,"Piva":"xdfdff","RagioneSociale":"Kellner","RepositoryRegistrationDate":"\/Date(1366236000000+0200)\/","Stato":"DA VERIFICARE"},{"AnnoEsercizio":2013,"BatchID":636614,"CustomerDocumentTypeID":401,"Data":"\/Date(1357081200000+0100)\/","FileExtension":".jpg","FollowUp":null,"Frequenza":"TRIMESTRALE","Id":11,"Nota":null,"ObjectID":"6","PathBuildingRuleID":9,"Piva":"12345678901","RagioneSociale":"Alessio","RepositoryRegistrationDate":"\/Date(1366236000000+0200)\/","Stato":"OK"}]}---hirearchicaldatasource-----Master._resSolDataSource = new kendo.data.HierarchicalDataSource({ transport: { read: { beforeSend: function (xhr, s) { s.data = JSON.stringify(Master._filter); }, type: "POST", url: _rootUrl + 'wcf/ResponsabilitaSolidaleService.svc/getdocuments', contentType: "application/json; charset=utf-8", dataType: "json" } }, schema: { data: "GetDocumentsResult", model: { id: "Id", fields: { Id: { type: "number" }, Piva: { type: "string" }, RagioneSociale: { type: "string" }, Data: { type: "date" }, AnnoEsercizio: { type: "number" }, Frequenza: { type: "string" }, Stato: { type: "string" } }, children: "FollowUp" } }, group: { field: "RagioneSociale", dir: "asc" } });------and in the grid-----$("#adminGrid").kendoGrid({ ........, ...other code...., ....., columns: [{ field: "Id", hidden: true }, { field: "Piva", title: "Partiva IVA" }, { field: "RagioneSociale", title: "Ragione Sociale" }, { field: "Data", format: "{0:dd/MM/yyyy}" }, { field: "AnnoEsercizio", title: "Anno esercizio" }, { field: "Frequenza" }, { field: "Stato" }, { command: [ { name: "download", click: Master.download }, { name: "followup", click: Master.followup } ], title: " " }, { field: "FollowUp[0].FollowUp1", //<--FollowUp seems to be null title: "fu1 child" }] });function anonymous(data) {var o,e=kendo.htmlEncode;with(data){o='<tr data-uid="'+(data.uid)+'" role=\'row\'><td class="k-group-cell"> </td><td style="display:none" role=\'gridcell\'>'+e(data.Id==null?'':data.Id)+'</td><td role=\'gridcell\'>'+e(data.Piva==null?'':data.Piva)+'</td><td role=\'gridcell\'>'+e(data.RagioneSociale==null?'':data.RagioneSociale)+'</td><td role=\'gridcell\'>'+e(kendo.format("{0:dd/MM/yyyy}",data.Data==null?'':data.Data))+'</td><td role=\'gridcell\'>'+e(data.AnnoEsercizio==null?'':data.AnnoEsercizio)+'</td><td role=\'gridcell\'>'+e(data.Frequenza==null?'':data.Frequenza)+'</td><td role=\'gridcell\'>'+e(data.Stato==null?'':data.Stato)+'</td><td role=\'gridcell\'><a class="k-button k-button-icontext k-grid-download" href="#"><span class=" "></span>download</a><a class="k-button k-button-icontext k-grid-followup" href="#"><span class=" "></span>followup</a></td><td role=\'gridcell\'>'+e(data.FollowUp.FollowUp1==null?'':data.FollowUp.FollowUp1)+'</td></tr>';}return o;}