A function is a block of code that will be called several times during the execution. Instead of writing the same piece of code again and again, one can write this code inside a function and call that function whenever it is needed.
A function :
Private Function AddNumbers(X As Integer, Y As Integer) As Integer Return X + Y End Function
A Function Name, could be used as the return statement
Function sealBarTypeValidation() as Boolean Dim err As Boolean = False If rbSealBarType.SelectedValue = "" Then err = True End If Return err End Function
is just the same as
Function sealBarTypeValidation() as Boolean sealBarTypeValidation = False If rbSealBarType.SelectedValue = "" Then sealBarTypeValidation = True End If End Function