使用GroupView和loadonce为true时，Jqgrid不显示重新加载数据

Question

我正在使用带有loadonce的jqgrid 4.6和按列分组。我还根据给定here的分组文档对来自服务器的数据进行了排序。但是当我尝试使用以下代码重新加载数据时，我无法在网格中看到任何数据

jQuery("#RamTargetTable").jqGrid('setGridParam',{datatype:'json'}).trigger('reloadGrid');

以下是代码

jQuery("#RamTargetTable").jqGrid({
                    url: '<%=Url.Content("~/RamTarget/GetTargetData")%>',
                    width: 1220,
                    height: 250,
                    datatype: "json",
                    colNames: [my column names],
                    colModel: [my model],
                    emptyrecords: 'No Turbines found for the selected Plant',
                    searchoptions: { searchhidden: true },
                    mtype: 'GET',
                    loadonce: true,
                    hidegrid: false,
                    rowList: [],
                    pager: '#RamTargetTablePager',
                    viewrecords: true,
                    caption: "RAM Targets",
                    pgbuttons: false,
                    pginput: false,
                    pgtext: null,
                    grouping: true,
                    groupingView: {
                        groupField: ['SerialNumber'],
                        groupColumnShow: [true],
                        hideFirstGroupCol: [true]
                    },
                    editurl: '<%=Url.Content("~/RamTarget/AddEditRamTargets")%>',
                    checkOnSubmit: false,
                    reloadAfterSubmit: true
                });

                $('#RamTargetTable').jqGrid('navGrid', '#RamTargetTablePager', { edit: false, add: false, del: false, search: true});


function SendPlantId() {
                var plantId = $("#lstPlant").val() == null ? 0 : $("#lstPlant").val();
                $.ajax({
                    url: '<%=Url.Content("~/RamTarget/FilterGrid")%>',
                    type: "post",
                    data: { id: plantId, filter: "Plant" },
                    success: function(data) {
jQuery("#RamTargetTable").jqGrid('setGridParam',{datatype:'json'}).trigger('reloadGrid');
                               }
                    });
                   }