Textbox LostFocus event fires after Command Button's OnClick event

  • Thread starter Thread starter teddysnips
  • Start date Start date
T

teddysnips

WINDOWS FORMS

I've a form that has a textbox that allows the user to enter a string.
On the LostFocus event, the textbox formats the string into a preferred
format.

However, if the user presses the "Save" button while the textbox has
the focus, the LostFocus code doesn't run at the right time, so that
the "Save" function is dealing with an incorrectly formatted string and
the whole caboodle goes splat.

I like the LostFocus event, because I've got upwards of 14 such
textboxes on various tabs on the form, which all may contain different
strings but must all be formatted in the correct format. Here is the
function that handles this:

Private Sub txtTimeStartAndEndArbitrated(ByVal sender As Object,
ByVal e As System.EventArgs) Handles txtMonStartArbitrated.LostFocus,
txtMonEndArbitrated.LostFocus, _
txtTueStartArbitrated.LostFocus, txtTueEndArbitrated.LostFocus, _
txtWedStartArbitrated.LostFocus, txtWedEndArbitrated.LostFocus, _
txtThurStartArbitrated.LostFocus, txtThurEndArbitrated.LostFocus,
_
txtFriStartArbitrated.LostFocus, txtFriEndArbitrated.LostFocus, _
txtSatStartArbitrated.LostFocus, txtSatEndArbitrated.LostFocus, _
txtSunStartArbitrated.LostFocus, txtSunEndArbitrated.LostFocus

Dim txtTextBox As TextBox = CType(sender, TextBox)

txtTextBox.Text = FormatArbTime(txtTextBox.Text)

End Sub

Any thoughts?

Edward
 
Edward,

Why don't you set the enabled property to false on the save button and on
the lostfocus event, enable the save button, and on the gotfocus of each
textbox, set the enabled on the save button to false, until the textbox(es)
are populated?
--
Michael Bragg, President
eSolTec, Inc.
a 501(C)(3) organization
MS Authorized MAR
looking for used laptops for developmentally disabled.
 
(e-mail address removed) wrote:
[snip]

Thanks, guys, I'll give these a shot.

Edward
 
You can put a My.Application.DoEvents() call as the first statement in the
Buttons click event. The pending lost focus event will be fired and you can
then proceed with with the save logic.
 
no no no.. bad Terry, bad.

-Boo
You can put a My.Application.DoEvents() call as the first statement in
the Buttons click event. The pending lost focus event will be fired
and you can then proceed with with the save logic.
Click to expand...
 
Terry said:
You can put a My.Application.DoEvents() call as the first statement in the
Buttons click event. The pending lost focus event will be fired and you can
then proceed with with the save logic.
Click to expand...

Tried that - didn't work.

Edward
 
Dennis said:
Try using the textbox's "Validating" event..that's what it is for and should
work.
Click to expand...

Tried that - didn't work. The button's OnClick event still pre-empts
the textbox's Validating event.

Edward
 
Hello Terry,

Because it's not guaranteed. The results will be unpredictable.

The proper method, and the mechanism provided to do exactly this, is to use
the validating event.

-Boo
 
Hi Ghost,
Had never heard that (unpredictable) before - is this something
relevent to VS2005? Is it considered a bug? It seems to me that any
language construct that produces 'unpredicable' results should be considered
a bug.
I realize that the validating event is MS's prefered way to do this, the
problem is that there are bugs in this method such as using an escape key to
click the cancel button - does not work properly. Basically, my experience
is that using the validating event really only works if you are willing to
postpone all validation until the user presses the "ok' or 'Save' button. If
you want to validate as the user moves from control to control - the
validating event is a nightmare. Of course, I am no expert and if you have
some knowledge to the contrary or know of some trick, I am all ears!
 
Hello Terry,

It's not a bug or something 05-specific. You are attempting to control the
flow of events by massaging the message pump. By it's very nature this is
unpredictable. Any results you have which conform to your expectations are
purely coincidental and not by design.

On an architectural note.. I've always found the overhead of doing field
validation as the user inputs or immediately after they input to be a higher
cost than it's really worth. The ROI just isn't there. It's much easier
to fix any issues with the escape key/cancel button than it is to invent
a whole new validation scheme.

On a usability note, I absolutely hate using programs that force me to fix
input errors as I make them.. 95% of the time I dont make input errors..
and when I do it completely breaks my train of thought to have to stop, fix
something, and then move on. I'd rather get a summary of errors when Im
finished and have pressed the OK button.

-Boo
 
Hi Ghost,
Thanks for the input. I agree with you on *most* situations where the
user is entering data on a form. Validation can/should wait till the user
indicates that they are done. But, in some cases it can not. The kind of
apps that I work on most of the time fall into this catqagory. Often things
are changing with every keystroke (which is easier to handle) and whenever
the user navigates on the screen. I have never understood why a buttons
click event fires before the active control's lostfocus event, but it does
and going back to VB3, I have used the DoEvents call to handle any pending
lostfocus event. This has worked through VB6. I have not ported anything
to VB 2005 yet and based on what you are telling me, maybe I need to
reconsider how I do this.
Thanks again for taking the time,
 
Edward,
- What does your OnClick event look like?

Are you overriding the OnClick method or are you handling the Click event
itself?

If you are overriding the OnClick method are you calling the MyBase.OnClick
first, last or not calling it?

- Which version of .NET?

Using code similar in .NET 2.0 (VS 2005) to:

Private Sub TextBox1_LostFocus(ByVal sender As Object, ByVal e As
System.EventArgs) Handles TextBox1.LostFocus
Debug.WriteLine("TextBox1_LostFocus", Application.ProductName)
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Debug.WriteLine("Button1_Click", Application.ProductName)
End Sub

I am not able to reproduce the problem.


Using a custom button similar to:

Public Class Button
Inherits System.Windows.Forms.Button

Protected Overrides Sub OnClick(ByVal e As System.EventArgs)
Debug.WriteLine("OnClick", Application.ProductName)
MyBase.OnClick(e)
End Sub

End Class

I am not able to reproduce the problem (again in .NET 2.0).

- Which OS?

The above were tested on Windows XP Pro 32bit.

--
Hope this helps
Jay B. Harlow [MVP - Outlook]
..NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net


| WINDOWS FORMS
|
| I've a form that has a textbox that allows the user to enter a string.
| On the LostFocus event, the textbox formats the string into a preferred
| format.
|
| However, if the user presses the "Save" button while the textbox has
| the focus, the LostFocus code doesn't run at the right time, so that
| the "Save" function is dealing with an incorrectly formatted string and
| the whole caboodle goes splat.
|
| I like the LostFocus event, because I've got upwards of 14 such
| textboxes on various tabs on the form, which all may contain different
| strings but must all be formatted in the correct format. Here is the
| function that handles this:
|
| Private Sub txtTimeStartAndEndArbitrated(ByVal sender As Object,
| ByVal e As System.EventArgs) Handles txtMonStartArbitrated.LostFocus,
| txtMonEndArbitrated.LostFocus, _
| txtTueStartArbitrated.LostFocus, txtTueEndArbitrated.LostFocus, _
| txtWedStartArbitrated.LostFocus, txtWedEndArbitrated.LostFocus, _
| txtThurStartArbitrated.LostFocus, txtThurEndArbitrated.LostFocus,
| _
| txtFriStartArbitrated.LostFocus, txtFriEndArbitrated.LostFocus, _
| txtSatStartArbitrated.LostFocus, txtSatEndArbitrated.LostFocus, _
| txtSunStartArbitrated.LostFocus, txtSunEndArbitrated.LostFocus
|
| Dim txtTextBox As TextBox = CType(sender, TextBox)
|
| txtTextBox.Text = FormatArbTime(txtTextBox.Text)
|
| End Sub
|
| Any thoughts?
|
| Edward
|
 
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