Using the RequiredFieldValidator Class

As discussed in the In Depth section of this chapter, required field validators can determine if the user has entered data into a data-entry control or not. This validator is supported by the RequiredFieldValidator class; here is the inheritance hierarchy for that class:

Object
   Control
      WebControl
         Label
            BaseValidator
               RequiredFieldValidator

You can find the notable public properties of RequiredFieldValidator objects in Table 18.4. (This class has no non-inherited methods or events.) Note that as with other Web server controls, I am not listing the notable properties, methods, and events this class inherits from the Control and WebControl classes-you can find them in Chapter 15, Tables 15.1 to 15.5. This class inherits the BaseValidator class, which you can see in Tables 18.2 and 18.3, and this class also inherits the Label class; the Label class has only one non-inherited public member-the Text property, which holds the text the label displays.