Declaring control array

[Nathan]

If you're wondering why I post so many questions, it's because I want to
make an entry in the Guinness Book of World Records. But because I post so
many, I try to make them simple. Here is (I hope) a simple one:

I've declared a "control array" just after the WFD generated code like this:

Dim LabelArray() as Label = {Label0, Label1, Label2, Label3, Label4, Label5}

But when I try to do something like this:

\\
Private Sub FillLabels
dim a as integer
For a = 0 to 5
Msgbx(LabelArra y(a).Text)
Next
End Sub
\\

I get an "Object reference not set to an instance of an object" error. If I
put the Dim statement inside the subroutine, it works fine. Am I doing
something wrong in declaring the array to have class scope?

Once again, thanks for the help.

Nathan

[Armin Zingler]

"Nathan" <nk************ *********@softh ome.net> schrieb

I've declared a "control array" just after the WFD generated code
like this:

Dim LabelArray() as Label = {Label0, Label1, Label2, Label3, Label4,
Label5}

But when I try to do something like this:

\\
Private Sub FillLabels
dim a as integer
For a = 0 to 5
Msgbx(LabelArra y(a).Text)
Next
End Sub
\\

I get an "Object reference not set to an instance of an object"
error. If I put the Dim statement inside the subroutine, it works
fine. Am I doing something wrong in declaring the array to have
class scope?

The array is filled in the constructor before InitializeCompo nent is called
and consequently before Label0...Label5 have been set, so you are filling
the array with 6 x Nothing.
--
Armin

http://www.plig.net/nnq/nquote.html
http://www.netmeister.org/news/learn2quote.html

[Hexathioorthooxalate]

Nathan, I'd have it a guess that an instance of Label0, Label1, Label2,
Label3, Label4, and Label5 hasn't been created when you declare LabelArray
outside the subroutine FillLabels (and with class scope); LabelArray would
have length 5 but be full of 'Nothing'.

Within your for next loop, add a

if labelarray(a) is nothing then
msgbox "nothing"
end if

to see if this is the case. To elaborate further, if you have your
LabelArray declared at class level, derived from for example
System.Windows. Forms. Form, the "space" for the array will be allocated but
instances of the controls on the form Label0, .... won't have been. What you
are wanting is to populate LabelArray after Form_Load has executed - then
Label0, Label1... etc are instances of Label. As I see it when you are
running your application now, they probably aren't.

Regards
Hexathioorthoox alate

"Nathan" <nk************ *********@softh ome.net> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..

If you're wondering why I post so many questions, it's because I want to
make an entry in the Guinness Book of World Records. But because I post so many, I try to make them simple. Here is (I hope) a simple one:

I've declared a "control array" just after the WFD generated code like this:
Dim LabelArray() as Label = {Label0, Label1, Label2, Label3, Label4, Label5}
But when I try to do something like this:

\\
Private Sub FillLabels
dim a as integer
For a = 0 to 5
Msgbx(LabelArra y(a).Text)
Next
End Sub
\\

I get an "Object reference not set to an instance of an object" error. If I put the Dim statement inside the subroutine, it works fine. Am I doing
something wrong in declaring the array to have class scope?

Once again, thanks for the help.

Nathan

[Hexathioorthooxalate]

I mean length 6 :(
"Hexathioorthoo xalate" <ru***@spamerem ove.clara.co.uk > wrote in message
news:10******** ********@echo.u k.clara.net...

Nathan, I'd have it a guess that an instance of Label0, Label1, Label2,
Label3, Label4, and Label5 hasn't been created when you declare LabelArray
outside the subroutine FillLabels (and with class scope); LabelArray would
have length 5 but be full of 'Nothing'.

Within your for next loop, add a

if labelarray(a) is nothing then
msgbox "nothing"
end if

to see if this is the case. To elaborate further, if you have your
LabelArray declared at class level, derived from for example
System.Windows. Forms. Form, the "space" for the array will be allocated but instances of the controls on the form Label0, .... won't have been. What you are wanting is to populate LabelArray after Form_Load has executed - then
Label0, Label1... etc are instances of Label. As I see it when you are
running your application now, they probably aren't.

Regards
Hexathioorthoox alate

"Nathan" <nk************ *********@softh ome.net> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..

If you're wondering why I post so many questions, it's because I want to
make an entry in the Guinness Book of World Records. But because I post so

many, I try to make them simple. Here is (I hope) a simple one:

I've declared a "control array" just after the WFD generated code like

this:

Dim LabelArray() as Label = {Label0, Label1, Label2, Label3, Label4,

Label5}

But when I try to do something like this:

\\
Private Sub FillLabels
dim a as integer
For a = 0 to 5
Msgbx(LabelArra y(a).Text)
Next
End Sub
\\

I get an "Object reference not set to an instance of an object" error.

If I

put the Dim statement inside the subroutine, it works fine. Am I doing
something wrong in declaring the array to have class scope?

Once again, thanks for the help.

Nathan

[Cor]

Hi Nathan,

To add to the others how to resolve it

Dim LabelArray() as Label = {Label0, Label1, Label2, Label3, Label4, Label5}
\\
Private Sub FillLabels
dim a as integer
For a = 0 to 5
LabelArray(a) = new Label
Msgbx(LabelArra y(a).Text)
Next
End Sub
\\

I hope this helps,

Cor

[Armin Zingler]

"Cor" <no*@non.com> schrieb

Dim LabelArray() as Label = {Label0, Label1, Label2, Label3,
Label4,

Label5}

\\
Private Sub FillLabels
dim a as integer
For a = 0 to 5

LabelArray(a) = new Label

Msgbx(LabelArra y(a).Text)
Next
End Sub
\\

I hope this helps,

I don't think so. I think he wants the 6 labels in the array, not 6
invisible labels. ;-)
--
Armin

[Cor]

Hi Armin

I don't think so. I think he wants the 6 labels in the array, not 6
invisible labels. ;-)

Dim LabelArray() as Label = {Label0, Label1, Label2, Label3,
Label4,

Label5}

\\ Private Sub FillLabels
dim a as integer
For a = 0 to 5

LabelArray(a) = new Label
labelarray(i).W idth = 40
labelarray(i).H eight = 20
labelarray(i).L ocation = New System.Drawing. Point(10, Cint(i * 21))
labelarray(i).T ext = i.ToString
Me.Controls.Add (labelarray(i))

Msgbx(LabelArra y(a).Text)
Next
End Sub
\\

Better?

Cor

[Armin Zingler]

"Cor" <no*@non.com> schrieb

LabelArray(a) = new Label

labelarray(i).W idth = 40
labelarray(i).H eight = 20
labelarray(i).L ocation = New System.Drawing. Point(10, Cint(i *
21)) labelarray(i).T ext = i.ToString
Me.Controls.Add (labelarray(i))

Better?

Yes, but what I meant was that I'd created the array later because I think
the labels have been added by the designer.

Private Sub Form1_Load( _
ByVal sender As System.Object, _
ByVal e As System.EventArg s) Handles MyBase.Load

Me.LabelArray = New Label() _
{Label0, Label1, Label2, Label3, Label4, Label5}
End Sub

--
Armin

[Herfried K. Wagner [MVP]]

* "Nathan" <nk************ *********@softh ome.net> scripsit:

If you're wondering why I post so many questions, it's because I want to
make an entry in the Guinness Book of World Records. But because I post so
many, I try to make them simple. Here is (I hope) a simple one:

I've declared a "control array" just after the WFD generated code like this:

Dim LabelArray() as Label = {Label0, Label1, Label2, Label3, Label4, Label5}

But when I try to do something like this:

\\
Private Sub FillLabels
dim a as integer
For a = 0 to 5
Msgbx(LabelArra y(a).Text)
'MsgBox'...
Next
End Sub
\\

I get an "Object reference not set to an instance of an object" error. If I
put the Dim statement inside the subroutine, it works fine. Am I doing
something wrong in declaring the array to have class scope?

The code should work. Where do you call the procedure? In the form's
constructor prior to calling 'InitializeComp onent'? At this time, the
controls are not yet instantiated, so you will get the exception.

--
Herfried K. Wagner [MVP]
<http://www.mvps.org/dotnet>

[Nathan]

Thanks for the help so far. To be more specific, I already have the labels
created in the form designer, and I want to add them to a new array. The
array declaration appears after the form designer generated code, and just
before any other written code. I had guessed that for some reason the
labels didn't "exist" yet when the dim statement appeared. I still don't
understand why, though.

I put a msgbox in the for...loop as Hex suggested, and the msgbox appeared
as expected. The sub where the for...loop appears is called by the frm_Load
event. To give you a visual:

\\
+ Windows Form Designer generated code

Dim LabelArray() as Label = {Label0, Label1, Label2, Label3, Label4, Label5}

Private Sub frm1_Load(etc.. ..) Handles MyBase.Load
FillLabels()
End Sub

Private Sub FillLabels()
'Code...
End Sub
\\

I'm guessing that as a workaround I could delete the labels from the form
designer
and insert them via code (as per Cor's post), but surely there's another
way to make this work.