Mdi Form Validating

12 Jul 2006 6:59 PM

easoftware

I am using VS .Net 2003 and VB. I have an app with one parent and two
Mdi child forms. I need to validate data in the Mdi form. The
Form.Validating event works when I try to close a Mdi form, but not
when I try to switch form one Mdi form to the other. I tried to add
code to MdiForm1's Deactivate event:

    Private Sub MidForm1_Deactivate(ByVal sender As Object, ByVal e As
System.EventArgs) Handles MyBase.Deactivate

        Dim TempE As System.ComponentModel.CancelEventArgs
        TempE.Cancel = False
        MdiForm1_Validating(sender, TempE)
        If TempE.Cancel Then
            MdiForm1_Activated(sender, e)
        End If
    End Sub

but when MdiForm2 tries to load, the program crashes:

An unhandled exception of type 'System.OutOfMemoryException' occurred
in system.windows.forms.dll

Additional information: Error creating window handle.

How can I keep the focus in MdiForm1 when the user wants to change
forms and the data in MdiForm1 is not valid?

Thanks
Eric

13 Jul 2006 12:33 PM

tomb

I am guessing you mean when you switch from one child form to the
other. Why don't you try validating in the OnLostFocus override event?
Then you can regain focus.

T

easoftw***@gmail.com wrote:

Show quoteHide quote

>I am using VS .Net 2003 and VB. I have an app with one parent and two
>Mdi child forms. I need to validate data in the Mdi form. The
>Form.Validating event works when I try to close a Mdi form, but not
>when I try to switch form one Mdi form to the other. I tried to add
>code to MdiForm1's Deactivate event:
>
>    Private Sub MidForm1_Deactivate(ByVal sender As Object, ByVal e As
>System.EventArgs) Handles MyBase.Deactivate
>
>        Dim TempE As System.ComponentModel.CancelEventArgs
>        TempE.Cancel = False
>        MdiForm1_Validating(sender, TempE)
>        If TempE.Cancel Then
>            MdiForm1_Activated(sender, e)
>        End If
>    End Sub
>
>but when MdiForm2 tries to load, the program crashes:
>
>An unhandled exception of type 'System.OutOfMemoryException' occurred
>in system.windows.forms.dll
>
>Additional information: Error creating window handle.
>
>How can I keep the focus in MdiForm1 when the user wants to change
>forms and the data in MdiForm1 is not valid?
>
>Thanks
>Eric
>
>
>

13 Jul 2006 5:37 PM

easoftware

I would like the validating to test before the other MDI form gets
focus. Per VB documentation, the event order is:

1) Enter (Activated for Forms)
2) Got Focus
3) Leave (Deactivated for Forms)
4) Validating
5) Validated
6) Lost Focus

so, if the validating is in Lost Focus, the other form gets displayed
before the not valid error message can be shown. I would like to keep
the user in the form that is being validated.

tomb wrote:
Show quoteHide quote

> I am guessing you mean when you switch from one child form to the
> other. Why don't you try validating in the OnLostFocus override event?
> Then you can regain focus.
>
> T
>
> easoftw***@gmail.com wrote:
>
> >I am using VS .Net 2003 and VB. I have an app with one parent and two
> >Mdi child forms. I need to validate data in the Mdi form. The
> >Form.Validating event works when I try to close a Mdi form, but not
> >when I try to switch form one Mdi form to the other. I tried to add
> >code to MdiForm1's Deactivate event:
> >
> >    Private Sub MidForm1_Deactivate(ByVal sender As Object, ByVal e As
> >System.EventArgs) Handles MyBase.Deactivate
> >
> >        Dim TempE As System.ComponentModel.CancelEventArgs
> >        TempE.Cancel = False
> >        MdiForm1_Validating(sender, TempE)
> >        If TempE.Cancel Then
> >            MdiForm1_Activated(sender, e)
> >        End If
> >    End Sub
> >
> >but when MdiForm2 tries to load, the program crashes:
> >
> >An unhandled exception of type 'System.OutOfMemoryException' occurred
> >in system.windows.forms.dll
> >
> >Additional information: Error creating window handle.
> >
> >How can I keep the focus in MdiForm1 when the user wants to change
> >forms and the data in MdiForm1 is not valid?
> >
> >Thanks
> >Eric
> >
> >
> >

13 Jul 2006 6:56 PM

Barry

Hi,

Maybe you could check that ChildForm1 is valid in the ChildForm2
GotFocus. If it is valid then no problems - if it isn't switch back to
ChildForm1?

I haven't looked in to this properly - just an idea....

HTH

Barry

14 Jul 2006 10:07 PM

easoftware

Thanks for the help, but the problem with this approach is the number
of forms. In my example, there are only two, but my app will have
more. SO... I would have to check if Form#x is open, and it it is, is
the user editing, and if editing then validate. I would need to have
this code for every MDI form that could be open and editing data. I
would also have to do this in each form's GotFocus event. It would be
much cleaner to do the validation in the form with the data being
edited.

Barry wrote:
Show quoteHide quote

> Hi,
>
> Maybe you could check that ChildForm1 is valid in the ChildForm2
> GotFocus. If it is valid then no problems - if it isn't switch back to
> ChildForm1?
>
> I haven't looked in to this properly - just an idea....
>
> HTH
>
> Barry