However, for code readability, it would make sense to place all validation code in the Validating event.
So, which is the better option, in terms of both efficiency and industry-standards?
You should always use the Validating event, it was made to support validation.
If not to prevent the focus change then at least for the Causes Validation property.
Then :- Now Drag on Compare Validator to your design page where you want to show the error message(ofcourse if user is inputting some text in it). Write:- Now locate Controlto Validate option and write your control ID name in it(alternatively you can also select from drop down).
Also, the more tests you are performing, the slower your app might become. For more information regarding Regular Expressions, you are welcome to look at these two MSDN articles: Because it is always easy to learn by doing things practically, you will be creating an app that makes use of Regular Expressions to determine valid input. NET application and design the form to resemble Figure 1. Obviously this only works for the formatting of the email.Sometimes people are just trying to be funny, or they are literally trying to break your program. If the data is indeed only alphabetic letters (no symbols, no numbers or any other punctuation characters) the test succeeds and stores True inside the Name Valid variable. This is because it becomes more legible than just a normal set of numbers. You could say that a program's testers are supposed to do this; yes, they should - nobody else should. If not, if there is even just one unallowed character that is not supposed to be there, the Match method will return False. Instead of you having to loop through each character to determine what that character is, you simply need the correct Regular Expression pattern. Clear() Surname Valid = False Else Surname Valid = True End If End Sub It is basically the exact same code for the Name box, but I just included the capability to comprehend a space character as well. People expect to enter a phone number in a format similar to this: ###-###-####. You could add a Required Field Validator as well as a Range Validator (if that works for your case) or you could add a Custom Field Validator.Link to the Custom Field Validator: to MSDN Article on ASP. Visual Studio has got now integrated support for range checking and type checking :- Try this :- For RANGE CHECKING Before validating/checking for a particular range of numbers Switch on to design view from markup view .