Validating event in vb net
The sequence is the same regardless of how the end user moves the input focus away from the control. NET controls fire these events in the same sequence only if end users move the input focus by means of the keyword; if they use the mouse, the control fires a Lost Focus event, then the Validating event, and – if the validation fails – another Got Focus event to let the application know that the focus is again on the control. NET programs created by VB Migration Partner follow the . In most cases, the fact that the Lost Focus event fires before the Validate event doesn’t affect the application negatively.For example, consider the following VB6 code: Private Sub Text1_Got Focus() Text1.Working with instances of these classes allows the developer to provide robust error-handling solutions. NET Framework provides two general classes or exceptions that derive from the common An exception associated with the exception whose Inner Exception property you are accessing.This is helpful when a series of exceptions are involved.
The above code will cause the Validating event for each of your controls to be raised, ensuring that all the controls get validated, before the dialog is closed or the data is saved...Consistent use of these techniques will help make your applications more robust and reliable.When an application encounters an unexpected situation (such as a missing file or input parameter) or a logical error (performing a division-by-zero operation, for example), by default the application will terminate and generate an error display like the one shown in Figure 3.1. NET displays an error message and terminates the application when any error occurs.Back Color = vb Yellow End Sub Private Sub Text1_Lost Focus() Text1.Back Color = vb White End Sub Private Sub Text1_Validate(Cancel as Boolean) Cancel = (Text1. In some applications, however, the code in the Text1_Lost Focus method might depend on some variable that has been set in the Validate event.