Vb net validating combobox
The only way to solve this problem is to invoke the Validate Controls method from within the default Command Button control's Click event procedure.
The second flaw is that the Validate event doesn't fire when you're moving the focus from a control whose Causes Validation property is False, even if the control that receives the focus has its Causes Validation property set to True.
Typically, you do it when the user closes the form: Private Sub Form_Query Unload(Cancel As Integer, Unload Mode As Integer) ' You can't close this form without validating the current field.
Also, the more tests you are performing, the slower your app might become. For more information regarding Regular Expressions, you are welcome to look at these two MSDN articles: Because it is always easy to learn by doing things practically, you will be creating an app that makes use of Regular Expressions to determine valid input. NET application and design the form to resemble Figure 1. Obviously this only works for the formatting of the email.Fortunately, it doesn't take much to create a generic routine that forces each control on the form to validate itself: Private Sub Form_Query Unload(Cancel As Integer, Unload Mode As Integer) ' You can't close this form without validating all the fields on it. Set Focus If Err = 0 Then ' Don't validate controls that can't receive input focus.