I have a field name State, and I want that the value entered by the end user is force to Upper case.  What would be the best approach for this?

I know I can trap the control's TextChanged event and change the value there, but I am looking for a cleaner solution at the BO level so I don't have to do the modification in all form's this field may be used. 

I wish the Business Object Mapper could handle this kind things pretty much the way they handle the Trim.  It looks obvious to me this could be done in the BOM as an enhancement.