Form validating event vb net
A name doesn't generally contain weird symbols, and definitely not numbers. This can be from the mouse clicking inside another field, or a Tab key being pressed to navigate to the next input control. ") Else Email Valid = True 'Email is Perfect End If Else 'Not A Match To Pattern Email Valid = False 'Set Boolean Variable To False Message Box. I hope you have learned from this article and that you have enjoyed it as much as I did. That may seem like Captain Obvious speaking, but you'll be amazed at some of the data that gets entered into a name field. I then created an If statement to determine how the input data was formatted and whether or not the data is only alphabetic. There are 2 code paths for validation failure, and in each case we provide the user with an appropriate error message.The error provider simply takes a control and a message in the Set Error method and does the rest of the work for you!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.First, add the following code to the Form’s constructor after the Initialize Component method: This is a handy trick to prevent implicit validation of our controls when they lose focus.So, what I am trying to say is: make sure you understand other cultures, or be aware of people with uncommon names. Using Regular expressions here, is basically the standard, even though it is a bit messy. Focus() 'Return Focus End If End Sub Here, I created a separate function to do all the work. Add this to validate the surname textbox: Private Sub txt Surname_Leave(sender As Object, e As System. Leave 'Create A Pattern For Surname Dim str Surname As String = "^[a-z A-Z\s] $" Dim re Surname As New Regex(str Surname) 'Attach Pattern To Surname Textbox 'Not A Match If Not re Surname. Add the following code to validate your phone number textbox: 'Function To Check Phone Number Validity Public Function Validate Phone(By Val str Phone Num As String) As Boolean ''Create Reg Exp Pattern Dim str Phone Pattern As String = "^[1-9]\d-[1-9]\d-\d$" 'Create Reg Ex Object Dim re Phone As New Regex(str Phone Pattern) 'Something Typed In If Not String. This function is later called inside the textbox's Lost Focus event, which also fires when a control loses the focus. Keep in mind that each country has its own domain name, which sometimes will look like: Private Sub Validate Email() 'Set Up Reg Exp Pattern To Allow Most Characters, And No Special Characters Dim re Email As Regex = New Regex("([a-z A-Z0-9_\-\.] )@((\
They make use of a pattern matching system to match the input with a certain pattern of data.
In this case, we simply clear any error messages in the error provider.
The Name textbox works very similarly but we don’t have quite as elaborate validation logic.
If the user enters invalid data they’ll see an icon shown in Figure 3.
After the validating event returns without being cancelled, meaning we have valid user input, then the validated event will be raised.