Validating event in vb net
Notice that in the previously described scenario – the end user moves the focus away with the mouse but the control fails to validate – then a pair of Lost Focus/Got Focus events is fired anyway (unlike VB6), but this is seldom a problem. NET textbox, which event handler is better to use: Validating or Leave?
A programmer can evaluate the state of the data at that point and react to any error in the data either by: Listing 5.4 illustrates the use of the Validate event procedure to perform validation and to decide whether or not to keep focus on the current control.LISTING 5.4 USING THE VALIDATE EVENT PROCEDURE Private Sub txt Age_Validate(Cancel As Boolean) If Not Is Numeric(txt Age. The first Quick Tip Validation Guide defined validation as "the process of checking whether entered data is what it needs to be for the system to work correctly." And I noted in that article that: Windows form controls that have a Causes Validation property can fire a whole family of events when the focus shifts from the control.The Validate event and the accompanying Causes Validate property are new to VB6 and give programmers a much-needed replacement for older, more cumbersome techniques of field validation.
(See the section in this chapter entitled "Validation With Got Focus and Lost Focus Events".) In general, the best time to validate a field's contents is when the user attempts to leave the field.
One, remove the "control Box" from the form, so the user cant close it that way. in the btn Cancel_Click event: Removehandeler Text Box1.validating, Addressof Text Box1_Validating -- Terry "Darin" wrote: I know that, but the problem is when the user clicks EXIT, the textbox.validating event is called BEFORE the cancel.click is done, so the textbox is being validated. According to the documentation: "The cancel button for a form is the button control that is clicked whenever the user presses the ESC key." Which says to me the behavior s/b the same! To Short Date String Else Msg Box("Please enter a valid date.") e.