Hi Jose Simas,
You can just set the cell as invalid. That way the user won't be able to complete the edit operation until the cell contains a valid value and the underlying data for the cell won't be modified.
the Telerik team
Registration for Q1 2011 What’s New Webinar Week is now open. Mark your calendar for the week starting March 21st and book your seat
for a walk through all the exciting stuff we ship with the new release!