RadSpreadProcessing doesn't support this feature and we have it already in our backlog. You could vote for its implementation and track its progress through the related public item
Meanwhile, you could make a rough calculation how many columns are fitting in some particular page size with 100% scale factor. In order to make this calculation, you could use the PageSize property of WorksheetPageSetup
and subtract the corresponding margin values (from the Margins property) from the width.
Hope this helps.
Check out the Windows Forms project converter, which aids the conversion process from standard Windows Forms applications written in C# or VB to Telerik UI for WinForms.For more information check out this blog post
and share your thoughts.