Thank you for reporting this issue to us.
We are able to replicate the IndexOutOfRangeException on our end while using the latest version of Aspose.Cells for .NET 7.6.1 and your provided source code snippet. In order to investigate the said problem in more detail, a ticket has been logged in our bug tracking system under Id CELLSNET-42168. Please spare us little time to properly analyze the problem cause and to provide a fix at earliest. In meanwhile, we will keep you posted with updates.
Please accept our apologies for your inconvenience.
This is to inform you that we have fixed your issue. We will soon provide you the fixed version after performing QA and incorporating other enhancements and fixes.
Please try our latest version/fix: Aspose.Cells for .NET v19.6.1 (attached)
Your issue should be fixed in it.
Let us know your feedback.
Aspose.Cells19.6.1 For .Net2_AuthenticodeSigned.Zip (4.9 MB)
Aspose.Cells19.6.1 For .Net4.0.Zip (4.9 MB)