3.4. Requiring Data to Match a Predefined Pattern
You need to make sure the data a user enters matches a specific pattern, such as an email address.
RegularExpressionValidator control to the .aspx file, set the regular expression to perform the pattern matching, and verify that validation was successful from within the event handler of the control that completes the user’s entry for the page.
In the .aspx file:
RegularExpressionValidatorcontrol for each text box that must have data matching a specific pattern.
ValidationExpressionattribute of the
RegularExpressionValidatorto the regular expression needed to match the required pattern.
Add Save and Cancel (or equivalently named) buttons.
Set the Save button’s
Trueto have validation performed when the button is clicked (set it to
Falsefor the Cancel button).
In the code-behind class for the page, use the .NET language of your choice to add code to the event handler for the Save button’s click event to check the
Page.IsValid property and verify that all validation was successful. (See Recipe 3.1 for details.)
Figure 3-7 shows a typical form with normal, error-free output. Figure 3-8 shows the error message that appears on the form when an invalid email address is entered. Example 3-6 shows the .aspx file for our application that implements the recipe. (See Examples 3-2 and 3-3 [Recipe 3.1] for the companion code-behind files.)
One of the more common uses of pattern ...