The repro project I have provided in an attached email to support.
However the simple scenario involves
opening , closing, re-opening, closing and re-opening spreadsheets which eventually will trigger the following exception opening a excel file which it has previously opened. (Generally happens on the 4th or 5th date change and hence file open)
System.NullReferenceException
HResult=0x80004003
Message=Object reference not set to an instance of an object.
Source=Syncfusion.XlsIO.Base
StackTrace:
at Syncfusion.XlsIO.Implementation.WorksheetImpl.GetValue(ICellPositionFormat cell, Boolean preserveOLEDate)
at Syncfusion.XlsIO.Implementation.RangeImpl.get_Value()
at Syncfusion.Windows.Forms.Spreadsheet.Helpers.FormulaHelper.ReadCalcChainXMLElements(Spreadsheet sfSpreadsheet, String xml)
at Syncfusion.Windows.Forms.Spreadsheet.Helpers.FormulaHelper.OpenWorkbookInZipArchive(Stream fileStream, Spreadsheet sfSpreadsheet)
at Syncfusion.Windows.Forms.Spreadsheet.Spreadsheet.<>c__DisplayClass2f.<StartFormulaThread>b__2e()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
Sending a PM email with the repro project.