Is there a way to use the UltraValidator to compare the values of two or more controls? For example; one of three textboxes must not be null. What's the best way to do this using UltraValidator?
Implement Infragistics.Win.ICondition, which is a very simple interface, and assign the implementation to the ValidationSettings.Condition property. The implementation would probably take references to the controls that are players in the validation, then the ICondition.Matches method would check whatever criteria you want to enforce, and return true or false accordingly to signify whether it passes validation.