You can change the data validation error message by setting the ErrorMessage and Text properties of a Validator control. The ErrorMessage property of a validation control is displayed in a pop-up
window while the Text property is displayed at the location of the validator on the web page. This property is set at design time, but can be changed via the tags Property Sheet. To change it, you simply
add or modify the pass-through attributes located under the Custom attributes of the FieldValue tag.
You can only set the RequiredFieldValidator for a control. Additional validation can be implemented by overriding the Validate() method at the RecordControl class.
