TextField.ValidationError
From Xojo Documentation
Event
TextField.ValidationError(InvalidText as String,StartPosition as Integer)
New in 5.5
Supported for all project types and targets.
New in 5.5
Supported for all project types and targets.
The user has tried to enter a character that is prohibited by the TextField's Mask property.
Notes
InvalidText is the entire character string up to and including the invalid text. StartPosition is the starting character position in which the actual invalid text was entered. The first character is numbered 1. If no code is provided in this event and a validation error occurs, you will hear the default system beep.