Every control has a DataBindings collection... the first element of which should contain the Binding object that we create and attach to the control. The Binding object itself has a Format event that is raised when the data is being copied into the control. You can handle the Format event and modify the value within the event args and programmatically change the value that is being sent to the control.You'll also have to bind to the DataBindings.CollectionChanged event so you attach to the Format event of any new binding that is added to the collection. For an example on how to do this, you can check the Infragistics wrapper's UltraDateTimeEditor... I had to handle the Format to get the date to display NULL values properly.