Thanks for your posting and using Aspose.Cells.GridWeb.
We were able to replicate this issue using the latest version: after executing your sample code with your sample excel file. We found that if we use HtmlHiddenColDisplayType.Remove then chart is empty and if we comment this line, then chart is good.
We have logged this issue in our database for investigation. We will look into it and fix this issue. Once the issue is resolved or we have some other update for you, we will let you know asap.
This issue has been logged as
- CELLSNET-44073 - Converting to HTML with HtmlHiddenColDisplayType.Remove creates empty Chart
I have also attached the html generated with your code with and without HtmlHiddenColDisplayType.Remove for a reference.
Thanks for using Aspose.Cells.
Please download and try the latest .NET fix: Aspose.Cells for .NET v220.127.116.11 and let us know your feedback.