The input box validators are:
- the DateInputBoxValidator
- the TimeInputBoxValidator
- the TimeSpanInputBoxValidator
These validators are all inherited from the ASP.NET BaseValidator class and are
specifically designed to check the validity of the user input; an error message
is displayed if the input is deemed to be invalid.
These validators were designed because:
- the DateInputBox, TimeInputBox and TimeSpanInputBox controls require a method to
assess whether user input is valid
- it is best practice to inform the user where any errors have occurred and preferably
give guidance on how to correct these errors