Validating Input with the RegularExpressionValidator
Many forms of user input must be entered in very particular formats. For example, when asking for a user's e-mail address, the provided address must follow the following format: one to many alphanumeric characters, @, one to many alphanumeric characters, period, top-level domain name, such as com, net, org, edu, us, uk, fr, and so on.
For the ValidationControlTestBed.aspx ASP.NET Web page, the user is asked for a social security number. In the United States, every citizen is given a social security number, which contains nine digits and is typically written in the form
In order to ensure that a string input meets some specified format, we can use a RegularExpressionValidator, ...