Hi Margit Mathe,
Thank you for contacting us.
Another possibility is to clone your RadTreeView,
and change its size so that the entire content can be displayed. You can then use the TelerikPaintHelper.GetControlBmp
However, if you have many nodes in your RadTreeView
you will probably not want to create such a large control and will have to implement your own printing logic.
If you have any additional questions, please write us again.
the Telerik team