Try/Catch block within a Tab Page validating event

[chadwick]

Hi everyone -
I have a form that contains a TabControl object with 2 tab pages,
TabPage1 and TabPage2. TabPage1 contains two text boxes and a cancel
button, which closes the form.
I would like to validate the data contained in two text boxes on
TabPage1 before the user moves to TabPage2, using TabPage1's
validating event. My code looks like this:

Public Class TabPageValidati onTester

Private Sub ValidateTextBox es()
'Otherwise complex processing simplified here.
If TextBox1.Text = TextBox2.Text Then
Dim ex As New System.Exceptio n("Strings in _
TextBox1 and TextBox2 must be different.")
Throw ex
End If
End Sub

Private Sub TabPage1_Valida ting(ByVal sender As System.Object, _
ByVal e As
System.Componen tModel.CancelEv entArgs) _
Handles TabPage1.Valida ting
Try
ValidateTextBox es()
Catch ex As Exception
MessageBox.Show ("Error. " & ex.Message)
e.Cancel = True
End Try
End Sub

Private Sub btnCancel_Click (ByVal sender As System.Object, ByVal e
As System.EventArg s) Handles btnCancel.Click
Me.Close()
End Sub
End Class

[chadwick]

Re: Try/Catch block within a Tab Page validating event

On Apr 16, 2:14 pm, chadwick <chad.mi...@gma il.comwrote:

Hi everyone -
I have a form that contains a TabControl object with 2 tab pages,
TabPage1 and TabPage2. TabPage1 contains two text boxes and a cancel
button, which closes the form.
I would like to validate the data contained in two text boxes on
TabPage1 before the user moves to TabPage2, using TabPage1's
validating event. My code looks like this:
>
Public Class TabPageValidati onTester
>
Private Sub ValidateTextBox es()
'Otherwise complex processing simplified here.
If TextBox1.Text = TextBox2.Text Then
Dim ex As New System.Exceptio n("Strings in _
TextBox1 and TextBox2 must be different.")
Throw ex
End If
End Sub
>
Private Sub TabPage1_Valida ting(ByVal sender As System.Object, _
ByVal e As
System.Componen tModel.CancelEv entArgs) _
Handles TabPage1.Valida ting
Try
ValidateTextBox es()
Catch ex As Exception
MessageBox.Show ("Error. " & ex.Message)
e.Cancel = True
End Try
End Sub
>
Private Sub btnCancel_Click (ByVal sender As System.Object, ByVal e
As System.EventArg s) Handles btnCancel.Click
Me.Close()
End Sub
End Class

Sorry - accidentally posted before finishing my question. My problem
is this: if the user enters text in the boxes, the event successfully
cancels and the focus remains on TabPage1, but the Cancel button on
TabPage1 loses its functionality! That is, when the Cancel button is
clicked, the btnCancel.Click ed event is no longer raised. I have no
idea what cause this. I would like my user to be able to hit cancel
and leave the form after attempting to enter information in the text
box and failing. Any help out there would be greatly appreciated.

[Steve Gerrard]

Re: Try/Catch block within a Tab Page validating event

chadwick wrote:

> Private Sub TabPage1_Valida ting(ByVal sender As System.Object, _
> ByVal e As
>System.Compone ntModel.CancelE ventArgs) _
>Handles TabPage1.Valida ting
> Try
> ValidateTextBox es()
> Catch ex As Exception
> MessageBox.Show ("Error. " & ex.Message)
> e.Cancel = True
> End Try
> End Sub
>>

>
Sorry - accidentally posted before finishing my question. My problem
is this: if the user enters text in the boxes, the event successfully
cancels and the focus remains on TabPage1, but the Cancel button on
TabPage1 loses its functionality! That is, when the Cancel button is
clicked, the btnCancel.Click ed event is no longer raised. I have no
idea what cause this. I would like my user to be able to hit cancel
and leave the form after attempting to enter information in the text
box and failing. Any help out there would be greatly appreciated.

The issue is that if you cancel in the validating event of TabPage1, the focus
can't move to the Cancel button. A cancelled validation is basically modal, and
must be corrected before you can do anything.

Fortunately, the fix is easy. Set btnCancel.Cause sValidation = False. :)

[Cor Ligthert[MVP]]

Re: Try/Catch block within a Tab Page validating event

Chadwick,

AFAIK is there is no tabpage closing event only a tabpage changed event, so
this will in my idea be inpossible, however don't be afraid, the user won't
see it as you set the selected page back to the one it was.

Cor

"chadwick" <chad.mills@gma il.comschreef in bericht
news:22e4663d-2677-47f7-83df-c7f69ad870b3@q1 0g2000prf.googl egroups.com...

On Apr 16, 2:14 pm, chadwick <chad.mi...@gma il.comwrote:

>Hi everyone -
> I have a form that contains a TabControl object with 2 tab pages,
>TabPage1 and TabPage2. TabPage1 contains two text boxes and a cancel
>button, which closes the form.
> I would like to validate the data contained in two text boxes on
>TabPage1 before the user moves to TabPage2, using TabPage1's
>validating event. My code looks like this:
>>
>Public Class TabPageValidati onTester
>>
> Private Sub ValidateTextBox es()
> 'Otherwise complex processing simplified here.
> If TextBox1.Text = TextBox2.Text Then
> Dim ex As New System.Exceptio n("Strings in _
> TextBox1 and TextBox2 must be different.")
> Throw ex
> End If
> End Sub
>>
> Private Sub TabPage1_Valida ting(ByVal sender As System.Object, _
> ByVal e As
>System.Compone ntModel.CancelE ventArgs) _
>Handles TabPage1.Valida ting
> Try
> ValidateTextBox es()
> Catch ex As Exception
> MessageBox.Show ("Error. " & ex.Message)
> e.Cancel = True
> End Try
> End Sub
>>
> Private Sub btnCancel_Click (ByVal sender As System.Object, ByVal e
>As System.EventArg s) Handles btnCancel.Click
> Me.Close()
> End Sub
>End Class

>
Sorry - accidentally posted before finishing my question. My problem
is this: if the user enters text in the boxes, the event successfully
cancels and the focus remains on TabPage1, but the Cancel button on
TabPage1 loses its functionality! That is, when the Cancel button is
clicked, the btnCancel.Click ed event is no longer raised. I have no
idea what cause this. I would like my user to be able to hit cancel
and leave the form after attempting to enter information in the text
box and failing. Any help out there would be greatly appreciated.

[chadwick]

Re: Try/Catch block within a Tab Page validating event

Hi Steve - thanks for your reply. I have tried setting
btnCancel.Cause sValidation = False, but it didn't seem to work.

An interesting note: the code works perfectly if I comment out the
MessageBox.Show command:

Public Class TabPageValidati onTester

Private Sub ValidateTextBox es()
'Otherwise complex processing simplified here.
If TextBox1.Text = TextBox2.Text Then
Dim ex As New System.Exceptio n("Strings in " _
& "TextBox1 and TextBox2 must be different.")
Throw ex
End If
End Sub

Private Sub TabPage1_Valida ting(ByVal sender As System.Object, _
ByVal e As
System.Componen tModel.CancelEv entArgs) _
Handles TabPage1.Valida ting
Try
ValidateTextBox es()
Catch ex As Exception
'MessageBox.Sho w("Error. " & ex.Message)
e.Cancel = True
End Try
End Sub

Private Sub btnCancel_Click (ByVal sender As System.Object, ByVal e
_
As System.EventArg s) Handles
btnCancel.Click
Me.Close()
End Sub
End Class

I think my issue is related to the fact that the MessageBox.Show
command takes focus away from the controls on TabPage1, but I can’t
figure out the details. I could use an ErrorProvider, which would
probably work, but ErrorProviders aren't stark enough for my purposes
and I'd prefer to us a MessageBox. Any further ideas out there?

[Steve Gerrard]

Re: Try/Catch block within a Tab Page validating event

chadwick wrote:

Hi Steve - thanks for your reply. I have tried setting
btnCancel.Cause sValidation = False, but it didn't seem to work.
>

Odd. I copy/pasted your code, and it worked fine for me.