Hi ASPOSE Support,
I have observed your comments and request you to please provide the working sample project including all source files along with generated output file with us. Please also share the expected output file that you ought to generate using Aspose.Slides.
Source Code and template file attached.
I have observed the generated chart and have also worked with the sample code along with source presentation. The chart generated by code is different than that of what is shared by you. However, you can set the number format for chart data cell using using following sample code.
fact.GetCell(defaultWorksheetIndex, i + 1, 0, categoriesName[i] );
fact.GetCell(defaultWorksheetIndex, i + 1, 0).PresetNumberFormat = 14;
Please also visit this documentation link for your kind reference in this regard. I hope this will be helpful.