LostFocus Event Problem

[dollygoh]

Hi,

I have a form with 2 textboxes and a command button.
There are some codes written on the LostFocus event of
textbox1. The codes are as follow :

Private Sub textbox1_LostFocus()
If Not IsNumeric(Trim(textbox1.Text) Then
MsgBox "Please enter a numeric value !", vbOKOnly +
vbCritical, "ERROR"

End If
End Sub

To test on the code, I key in some characters in textbox1 & click
the command button. The message as shown above was displayed. But the codes of the command button was not executed. Does anyone know where has gone wrong ? Thanks !

Dolly

[mendhak]

If you press F8, you can step thru the code and see the sequence in which the code is executed. My guess is that when u press the command button, two things happen: text1 loses focus, and command1 is clicked. text1 probably gets executed first.

So you should step thru, and observe flow of execution.

[dollygoh]

Yes, textbox1 lostfocus after clicking the command button.
But I expect the codes in the command button to execute
as well, after I click the OK button of the MsgBox.
The lostfocus codes has to be there. What can I do to
ensure that codes in the command button will eventually be
executed ?
Thanks

[mendhak]

It's due to the presence of the check on the textbox1 value that the command button won't execute.

If you enter a numeric value, the code WILL execute.

is this what you wanted, or do you want the command button's code to be executed no matter what?

[dollygoh]

The command button acts as an exit button, that is, it will
close the form even if the user key in a non-numeric value in
textbox1. If user have to key in a numeric value in the textbox
before clicking on the exit button, he will get frustrated.

[Swatty]

Don't use the lostfocus event for it.

Use the change event instead.

The lostfocus event isn't such a good option.

[James Stanich]

Could you use validate?

Private Sub Text1_Validate(Cancel As Boolean)
 
End Sub

This fires before the lostfocus event and allows you to cancel if necessary...

[Buzby]

You should NOT use the LostFocus event for validating controls. Since VB6 a Validate event has appeared which should be used for this:

Private Sub textbox1_Validate(Cancel as boolean) 
If Not IsNumeric(Trim(textbox1.Text) Then 
MsgBox "Please enter a numeric value !", vbOKOnly + 
vbCritical, "ERROR" 
Cancel=true
End If 
End Sub

Then, on the button, set the CausesValidation property to FALSE and then the validate event for the control losing focus when you press the button will not be fired. Useful for CANCEL buttons etc.

[dollygoh]

Hi all,
Thanks for your replies.

By the way Buzby, I need to use the lostfocus event not only
for validating the controls, I also need to do some calculation
& display the result in textbox2. The result has to be displayed
automatically once some value is key in textbox1.

Now, if user key in some non-numeric value in textbox but later
wish to close the form without having to view the result in textbox2, is it possible to do that ?

I was thinking of validating the controls using the method you have just mention while doing the calculation & displaying the result in textbox2 using the lostfocus event of textbox1. Textbox2 is disabled & user can't key in any value.

Is setting the Cancel variable of the validate event to true stop the execution of the codes in lostfocus event when the command button is clicked ? Thanks!

[Buzby]

1. The LostFocus event should be used for code that should run EVERY TIME the control loses focus - ie, updating other controls etc.

2. The Validate event should be used for validation - and as I said before, you can select whether this event is run when a button is clicked - if you set Cancel=TRUE in a Validate event the focus remains with the control. Ie, the user cannot leave the control until the Validate event is happy!

3. Normally, you leave CausesValidation = TRUE on the OK, Save, etc buttons, and switch it to FALSE for the Cancel, Exit etc buttons. That way if a user wants to cancel the form/program they are not forced to get the current control validated first.

[MartinLiss]

If you would like to limit the textbox to numbers (and optionally specify such things as if it can or cannot be negative or if it can have decimals) you can download a control that I wrote. You can find it in my post inthis thread

[dollygoh]

I have tried to set the CausesValidation property of my exit button to false but the validate event of textbox1 still executed when I key in some non-numeric value to textbox1 and then click
the command button (cmdExit). I thought that after setting CausesValidation property to false, the validate event should not be executed, did I miss out anything in my code as shown below?

Private Sub textbox1_Validate(Cancel as boolean)
If Not IsNumeric(Trim(textbox1.Text) Then
MsgBox "Please enter a numeric value !", vbOKOnly +
vbCritical, "ERROR"
Cancel=true
End If
End Sub

Private Sub cmdExit_Click()
Unload Me
End Sub

[Buzby]

Well when I use it it works as I would expect - are you sure you have got rid of the code in the LostFocus event of the textbox.

Set up a simple form with a textbox and a button.

In the textbox's validate event put:

Private Sub Text1_Validate(Cancel As Boolean)
Debug.Print "Validate"
End Sub

Then run the program with the CausesValidation event switched to FALSE on the button - if the focus is in the textbox and you click on the button you should NOT see "Validate" turn up in the Immediate window - ie the Validate event is not being run.

[dollygoh]

Thanks for all your help.

I have found the "bug" in my program.
The CausesValidation can't work because at certain part of the code, I have accidentally set the Enabled property of the command button to false.