Jquery jqGrid导航器重新加载

我有一个jqgrid导航器，可以将网格导出到csv中

$('#jqgEndYear').jqGrid('navGrid', '#jqgpEndYear',
                { excel: true, add: false, del: false, edit: false, search: false },
                {}, {}, {});
$("#jqgEndYear").jqGrid('navButtonAdd', '#jqgpEndYear', {
                caption: "",
                onClickButton: function () {
                    alert(mapping);
                    $.post('@Url.Action("ExportEndYearSummaryToCsv")', {
                        clientId: '@Model.Division.Client.ClientID',
                        globalId: '@Model.GlobalId',
                        firstName: '@Model.FirstName',
                        lastName: '@Model.LastName',
                        mapping: mapping,
                        yearEnd: year
                    }, function (data) {
                        window.location.href = data;
                    });
                }
            });

提交表单时，将填充我的jqGrid

 $('#reviewButton').click(function () {
        var year = $('#YearList').val();
        var mapping = $.trim($('#MappingList').val());          
        if (!firstClick) {
            var postdata = $("#jqgEndYear").jqGrid('getGridParam', 'postData');
            postdata.yearEnd = year;
            postdata.mapping = mapping;
            $("#jqgEndYear").trigger("reloadGrid");
        }
        else {
            firstClick = false;
            $('#jqgEndYear').jqGrid({
                //url from wich data should be requested
                url: '@Url.Action("YearEndReview")',
                //type of data
                datatype: 'json',
                //url access method type
                mtype: 'POST',
                postData: { mapping: mapping, yearEnd: year, clientId: '@Model.Division.Client.ClientID', globalId: '@Model.GlobalId' },
                ....
         }

由于导航器是在第一次单击时定义的，如果我再次提交表单，“mapping”和“year”的值仍然是导出文章中的旧值

我怎样才能解决这个问题

提前谢谢