Introduction to the RegularExpressionValidator Control
The RegularExpressionValidator control performs validation by comparing the user input to the regular expression pattern specified in itsproperty. You can write your own regular expressions or select from a list of predefined expressions. For details, see .
If the user input value in the targeted control does not match the regular expression in the ValidationExpression property, the RegularExpressionValidator control displays the text defined in itsproperty.
When you add a RegularExpressionValidator control to a container control or template:
The ErrorMessage property is set to "RegularExpressionValidator".
Theproperty is set to "error", which is the name of a predefined style in the default instance.