Nested tabcontrol - error - Object reference not set to an instance of an object.

[mshmyob]

I am using VS2008 and vb.net

I have a nested tabcontrol.

tabControl 1 and tabControl3

In tabControl3 I am trying to populate a text control with a value from a control placed on tabControl1.

' add a savings tabpage
Dim strSavingsPage As String
Dim dblTaxRate As Double
dblTaxRate = Me.txtRetirementTaxRate.Text
       For Each tabpg As TabPage In SavingsAllTabPages
            If Not TabControl3.Contains(tabpg) Then
                TabControl3.TabPages.Add(tabpg)
                tabpg.Text = "Savings"
                tabpg.Focus()
                strSavingsPage = Mid(tabpg.Name, 11)
                Me.Controls("txtWithdrawRate" & strSavingsPage).Text = dblTaxRate
                Exit For
            End If
        Next
 

The error occurs on the following line:

Me.Controls("txtWithdrawRate" & strSavingsPage).Text = dblTaxRate
 

If I change the line to

Me.txtWithdrawRate1.Text = dblTaxRate
 

everything works fine.

The complete error is:

NullReference exception was unhandled
Object reference not set to an instance of an object.

I am probably doing something obvious but vb.net is not my strong point.

Any ideas?

cheers,

[Rabbit]

Are you sure strSavingsPage is outputting correctly? Did you do a message box to output the value and length to make sure it's correct?

[mshmyob]

Hello Rabbit,

Yeah that was the first thing I did. I again just verified it and the value is correct.

cheers,

[Rabbit]

Does this work?
Me.Controls("txtWithdrawRate1").Text = dblTaxRate

[mshmyob]

Nope - same error.

I have tried referencing the control as far back as the forms container but still have the same error.

This is driving me crazy. As a work around I am currently using a SELECT CASE but would rather bring it down to this single statement.

cheers,

[mshmyob]

I am thinking it has something to do with referencing the complete container. Maybe I am not getting the sequence correct.

Lets assume names like so:

Form = form1
main tabControl = tabControl1
main tabcontrol page index = 1 (ie: 2nd page)
nested tabcontrol = tabControl2
nested tabcontrol page index = 0 (ie: 1st page)
groupbox = group1
textbox control = textbox1

How would I create the complete reference to the textbox control starting with the form container? The textbox is in the groupbox container on the first tab page of the nested tabcontrol.

cheers,

[mshmyob]

Got it Rabbit.

You do have to refer to the original container. replaced the line in question with the following 2 lines

Dim cntlYou As Control = tabpg.Controls("grpYou" & strSavingsPage).Controls("grpTaxable" & strSavingsPage).Controls("txtWithdrawRate" & strSavingsPage)
cntlYou.Text = dblTaxRate
 

I also had it all inside another group box so I had to reference that container also.

Thanks for all your help, I appreciate it.

cheers,