Validating event of text box in vb net
Hi All, I am writing a simple win form which contains a button, when user click the button i want to validate all the other textbox and see if there is anything goes wrong may i know how can i trigger the validating event for all text box? thx and regard,s Norton Norton, It sounds for me as a horse behind the car.
thx and regard,s Norton Norton, I got the following tip from "Windows Forms Programming in C#" by Chris Sells, from Addison Wesley. How can something be wrong in a textbox when you use correct the validating event.
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.
NET controls is in the order in which they fire the Lost Focus and Validate events.
As you'll see in a moment, the Visual Basic 6 approach is simple and clean; it really astonishes me that it took six language versions to deliver such a lifesaver.
If this property is True, Visual Basic fires the Validate event in the control that's about to lose the focus, thus giving the programmer a chance to validate its contents and, if necessary, cancel the focus shift. Imagine that you have five controls on a form: a required field (a Text Box control, txt Required, that can't contain an empty string), a numeric field, txt Numeric, that expects a value in the range 1 through 1000, and three push buttons: OK, Cancel, and Help.
(See the figure below.) You don't want to perform validation if the user presses the Cancel or Help buttons, so you set their Causes Validation properties to False.
Run(form1) End Sub End Class Public Class Form1 Inherits System. Protected Overloads Overrides Sub Dispose(By Val disposing As Boolean) If disposing Then If Not (components Is Nothing) Then components. Dispose(disposing) End Sub Friend With Events Text Box1 As System.
Printing Public Class Main Class Shared Sub Main() Dim form1 As Form = New Form1() Application. Initialize Component() 'Add any initialization after the Initialize Component() call End Sub 'Form overrides dispose to clean up the component list.