Each new exception can preserve the information about the previous one by storing it in this property.Let’s assume when we click our save button that we wish to validate the controls and display an icon if there is a problem.However, I prefer to call it explicitly and handle all validation at once since you most likely will take action only if the entire control’s children pass validation. The most important thing to recognize here is how precise you can be with the validation error message in the error provider.There are 2 code paths for validation failure, and in each case we provide the user with an appropriate error message.Unhandled errors in an application can result in unexpected termination, lost data, and potentially even create security holes if input values are not properly restricted.The Common Language Runtime (CLR) represents all errors as exceptions. The Framework class library (FCL) includes a large number of standard exception classes that encapsulate information about common errors.
The user might delete a critical file or enter invalid data.
A network link to a server might fail just as you're transferring data.
Or perhaps you simply didn't allow for a particular rare circumstance in your code. NET Framework offers a robust set of tools for dealing with these unexpected problems.
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: ###-###-####.