Hello Marco, 

Thank you for the post. Unfortunately including week number is not possible, we relay on .net custom format string only.

Regards,

Sure , here is the link to lean more about GantView ,Just to know that our UltraWinSchedule controls resemble closely to that of Microsoft Outlook's viewstyle .

And if you have sample browser install ,you can have samples of all the available controls of winform for more learning.