I ran into an interesting use case. We generate excel 2003 files programatically using Aspose for our users. They make changes to the excel document and then upload it back and we process the changes. The problem case I found was when a user has excel 2007 installed and they open up our 2003 file and then save their changes the .xls file gets saved as .xlsx. When the user uploads the file back to use we get the following exception from the .Open command.
Any ideas? Im using the latest trial version of Aspose.Cells.
string path = @"C:\Book1.xlsx";
Workbook workbook = null;
workbook = new Workbook();
workbook.Open(path, FileFormatType.Excel2007Xlsx); // <== exception thrown here
System.NullReferenceException: Object reference not set to an instance of an object.
at Aspose.Cells.OpenXML.xa969cda0bb1fbd14.x06b0e25aa6ad68a9(XmlTextReader xb9763b0038341e6c)
at Aspose.Cells.OpenXML.xe95a61e48a6637a3.x2e7f798eabefe5b4(Workbook xce16031e3118b903, Stream xcf18e5243f8d5fd3)
at Aspose.Cells.Workbook.Open(Stream stream, FileFormatType type)