Dynamic columns in ASP.NET MVC Grid with string property containing Json

[Jeffrey Stone]

I have a table that I am reading from a database and one of the columns contains Json Data all of which I am passing to the Grid. The content displays in the Grid. However, I receive the following error message when trying to export the Grid to Excel:

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Some of the relevant code:

public class GridRow

{    

        public string Symbol   get; set; }

        

        [Display(Name = "Entered Date")]

        [DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:MM/dd/yy HH:mm:ss}")]

        public DateTime Date { get; set; }

        [Display(Name = "Entered Quantity")]

        [DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:n0}")]

        public int Quantity { get; set; }

        // I am using JSON.NET and created a custom converter that will pass the Json text as is without any encoding

        [JsonConverter(typeof(JsonStringJsonConverter))]

        public string LogInformation { get; set; }

}

Html.EJ().Grid<GridRow>("TradesGrid").AllowFiltering().AllowPaging().AllowSorting().AllowTextWrap().HtmlAttributes(new Dictionary<string, object> { { " data-export-excel-url", Url.ExportTradesToExcel() } }).ShowColumnChooser().FilterSettings(filter => { filter.FilterType(FilterType.Excel); }).PageSettings(pg => pg.PageSize(10)).Columns(col =>

{

    col.Field(r => r.Date).Add();

    col.Field(r => r.Symbol).Template("<a class='symbol'>{{:Symbol}}</a>").Add();

    col.Field(r => r.Quantity).TextAlign(TextAlign.Right).Add();

    col.Field("LogInformation.BoundedPct").TextAlign(TextAlign.Right).Add();

    col.Field("LogInformation.TermStructure").Add();

})

The grid's data is being set through Ajax - and the data is used in multiple other areas on the page:

function refreshTradesGrid(backtestResultId) {

$.ajax({

type: "GET",

dataType: "json",

url: settings.getTradesUrl,

data: {

backtestResultId: backtestResultId

},

success: function(result) {

var jsonResult = ej.parseJSON(result);

settings.$tradesGrid.ejGrid("dataSource", jsonResult);

// use the trade data elsewhere on the page

refreshTradesPivotGrid(jsonResult, false);

refreshHistogramChart(jsonResult);

    }});

}

Full stack trace of the exception:

[NullReferenceException: Object reference not set to an instance of an object.]

Syncfusion.EJ.Export.GridExcelExport.ProcessRecordCell(Object row, Column column) +342

Syncfusion.EJ.Export.<>c__DisplayClass10.<ProcessRecordRow>b__f(Column column) +206

System.Collections.Generic.List`1.ForEach(Action`1 action) +85

Syncfusion.EJ.Export.GridExcelExport.ProcessRecordRow(Object row) +162

Syncfusion.EJ.Export.GridExcelExport.RenderRecord() +105

Syncfusion.EJ.Export.GridExcelExport.ProcessGridContents() +139

Syncfusion.EJ.Export.GridExcelExport.IterateElements() +315

Syncfusion.EJ.Export.GridExcelExport.ExportHandler() +13

Syncfusion.EJ.Export.GridExcelExport.ExecuteResult(GridProperties GridModel, Object dataSource) +418

Syncfusion.EJ.Export.GridExcelExport.ExportHelper(GridProperties gridModel, Object dataSource) +599

Syncfusion.EJ.Export.GridExcelExport.Export(GridProperties gridModel, Object dataSource, Boolean multipleExport) +18

Syncfusion.EJ.Export.ExcelExport.Export(GridProperties gridmaodel, Object datasource, String excelname, ExcelVersion excelversion, Boolean isHideColumnIncude, Boolean isTemplateColumnIclude, String theme) +101

Syncfusion.EJ.Export.ExcelExport.Export(GridProperties gridmaodel, IEnumerable datasource, String excelname, ExcelVersion excelversion, Boolean isHideColumnIncude, Boolean isTemplateColumnIclude, String theme) +30

JMS.EuclidWeb.Shared.ExportSyncFusionGrid.ExportToExcel(IEnumerable rows, GridProperties gridProperties, String fileName) in D:\Dropbox\Source\Euclid\Prod\EuclidWeb\Shared\ExportSyncFusionGrid.cs:134

JMS.EuclidWeb.Controllers.<ExportExitTradesToExcel>d__20.MoveNext() in D:\Dropbox\Source\Euclid\Prod\EuclidWeb\Controllers\BacktestResultController.cs:453

System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92

System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58

System.Web.Mvc.Async.TaskAsyncActionDescriptor.EndExecute(IAsyncResult asyncResult) +97

System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeAsynchronousActionMethod>b__36(IAsyncResult asyncResult) +17

System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10

System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +32

System.Web.Mvc.Async.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d() +50

System.Web.Mvc.Async.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() +225

System.Web.Mvc.Async.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult) +10

System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10

System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49

System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +34

System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +26

System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +100

System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10

System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49

System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27

System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13

System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29

System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49

System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36

System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +12

System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22

System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49

System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26

System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10

System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21

System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29

System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49

System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28

System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9

System.Web.CallHandlerExecutionStep.OnAsyncHandlerCompletion(IAsyncResult ar) +129

Regards, Jeff

[Saravanan Arunachalam]

Hi Jeffrey, 

Thanks for contacting Syncfusion’s support. 

We have already discussed this query in the following knowledge base document. 

https://www.syncfusion.com/kb/3018/null-exception-while-exporting  

Regards, 

Saravanan A.