Validating event visual basic
The previous article in this two part series focuses more on validation when Auto Validate is set to something else.
Since the article above covers that, in this article, assume that Auto Validate for the form is set to Disable so Explict validation will be required. Writeline statements to confirm what is actually happening in the code. The first is to call Validate from the event subroutine handling the event.
It's an old fashioned debugging technique, but it really helps me in this particular case. A call to Validate can be triggered by code elsewhere, but it still doesn't trigger the Validating and Validated events as shown below.--------Click Here to display the illustration--------The second is to call Validate from a container control where the controls that you want validated are child controls.
Click Here to read that article and then return to this one. For example, this might come in handy if you had a two stage validation. Writeline is the fastest and easiest way to check whether that actually happens.--------Click Here to display the illustration--------There are two 'explicit' validation methods:-Validate Children Both have two overloads. The Validate Method You might think that you can trigger the execution of the Validating or Validated events by calling Validate from, for example, a Button, but you can't.
Implicit validation occurs when Auto Validate for the form is set to Enable Prevent Focus Change (the default) or Enable Allow Focus Change. But each control has a Validating and Validated event with a Console. Here's a partial snippet: Private Sub Text Box1_Validating( By Val sender As Object, By Val e As System. In the first article, I noted that you can set ...... When Auto Validate is set to Disable, calling Validate does nothing, even though it might appear to 'work'.--------Click Here to display the illustration--------In this case, there are two ways to trigger the execution of the Validating and Validated events.
What Microsoft calls "implicit" validation is used most often. Write Line("Text Box1 Validated") End Sub Your validation code ...
By Dan Mabbutt 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.
Microsoft calls this "implicit validation" because the events are fired "implicitly" by . Microsoft refers to coding a call to the Validate or Validate Children method as "explicit validation".