Unfortunately, there isn't an out of the box way to create a copy of the workbook object. A possible workaround is to create a new workbook and copy each worksheet of the source workbook in it, as well as any other properties you would like to include. I've prepared a sample project illustrating this approach. It is by no means a comprehensive example, as it is limited to the content of the worksheets and the theme of the workbook. Other properties which can be included are for example the named ranges, the shapes and the name of the workbook.
I hope this helps.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.