Indeed ActiveWorksheet will be initialized when there are UI editor editing a specific worksheet. Instead, you can directly use the API of the WorksheetViewState for the worksheet that you get by index or by other means, for example:
Workbook workbook =
var worksheet = workbook.Worksheets.Add();
Let us know if you need additional information.
Get quickly onboarded and successful
with your Telerik and/or Kendo UI products with the Virtual Classroom free technical training, available to all active customers. Learn More.