Question

I have programmed a sub procedure that will be called in the main procedure (called by mainForm event), to validate the inputs before the main calculation. Now I’m searching for a way to cancel the calculation and refocus the mainForm if some inputs are mismatched. I think it’s unnecessary to use the Try-Catch statement to trap the error from calculation because I know its source and it should be prevented for the sake of code performance. Does someone have a solution this?

Answer 1

If you want to leave a subroutine early you just need to say Return.

Edit.

It sounds like you’re calling a method that calls another method. Have the second method return a Boolean indicating whether the input is valid. Something like this:

Public Sub CheckMainForm()
    'First validate the input
    If Not IsInputValid() Then Return
    'Next do the rest of your work
End Sub
Public Function IsInputValid() As Boolean
    'Do input validation, if at anypoint something is wrong return false
    If Not IsNumeric(txtAge.Text) Then Return False
    If Not IsValidEmail(txtEmail.Text) Then Return False
    Return True
End Function