Wierd For...Each behavior

[Tom]

This is very strange: I have a Windows Form with a Panel on it. In that
panel I dynamically (at run time) create some labels, as so:

for i=1 to x
dim ctlNew as New Label()
with ctlNew
.Name="Whatever " & trim(cstr(i))
.Text=.Name
.Visible=True
... etc etc etc ...
end with
MyPanel.Control s.Add(ctlNew)

This shows up fine when the form is displayed. However, I also have a reset
button on the form, which goes thru and destroys the labels, as such:

dim ctl as Control
for each ctl in MyPanel.Control s
if typeof ctl is Label then
ctl.text=""
ctl.visible=Fal se
ctl.Dispose()
end if
next

OK, here is the WIERD thing: The For...Each loop only seems to pick up the
EVEN or ODD numbered controls! It skips some of the controls (i.e. the odd
ones).... if I rerun the loop about three times, one right after the other,
it will finally pick up all the controls and get rid of them.

I -think- the code is correct - I even added a ctl=Nothing before and/or
after the ctl.Dispose(), but it didn't help. The For...Each loop just seems
the skip some of the label controls during its run. I am baffled ... even
though it is probably something dumb that I am doing.

Anyone got any ideas on this?

Tom

[Cor]

Tom,

dim ctl as Control
for each ctl in MyPanel.Control s
if typeof ctl is Label then
ctl.text=""
ctl.visible=Fal se
ctl.Dispose()
end if
next

I think that the collections in the for each loop is changed in the the for
each loop
I think that nicer is
For i = Me.Controls.Cou nt To 0 Step -1
Dim ctl As Control
it typeof ctl is Label then
Me.Controls.Rem ove(ctl)
Next
I hope this helps
Cor

[Scott Meddows]

Why don't you just set the labels to nothing? Dispose is called by the GC.
All you really have to do it kill your reference to the object. Let the GC
take care of the rest.
"Tom" <To*@nospam.com > wrote in message
news:ed******** ******@tk2msftn gp13.phx.gbl...

This is very strange: I have a Windows Form with a Panel on it. In that
panel I dynamically (at run time) create some labels, as so:

for i=1 to x
dim ctlNew as New Label()
with ctlNew
.Name="Whatever " & trim(cstr(i))
.Text=.Name
.Visible=True
... etc etc etc ...
end with
MyPanel.Control s.Add(ctlNew)

This shows up fine when the form is displayed. However, I also have a reset button on the form, which goes thru and destroys the labels, as such:

dim ctl as Control
for each ctl in MyPanel.Control s
if typeof ctl is Label then
ctl.text=""
ctl.visible=Fal se
ctl.Dispose()
end if
next

OK, here is the WIERD thing: The For...Each loop only seems to pick up the
EVEN or ODD numbered controls! It skips some of the controls (i.e. the odd
ones).... if I rerun the loop about three times, one right after the other, it will finally pick up all the controls and get rid of them.

I -think- the code is correct - I even added a ctl=Nothing before and/or
after the ctl.Dispose(), but it didn't help. The For...Each loop just seems the skip some of the label controls during its run. I am baffled ... even
though it is probably something dumb that I am doing.

Anyone got any ideas on this?

Tom

[Robert Jacobson]

Isn't Controls.Count a one-based index? I think it should be:

For i = Me.Controls.Cou nt -1 To 0 Step -1
....
"Cor" <no*@non.com> wrote in message
news:3f******** *************** @reader21.wxs.n l...

Tom,

dim ctl as Control
for each ctl in MyPanel.Control s
if typeof ctl is Label then
ctl.text=""
ctl.visible=Fal se
ctl.Dispose()
end if
next I think that the collections in the for each loop is changed in the the

for each loop
I think that nicer is
For i = Me.Controls.Cou nt To 0 Step -1
Dim ctl As Control
it typeof ctl is Label then
Me.Controls.Rem ove(ctl)
Next
I hope this helps
Cor

[Tom]

Yea, stupid me, I just figured this out when everyone replied. Sheesh, I
should have seen that. Anyway, I'll go in reverse and remove the items that
way. Thanks.

Tom

"Nak" <[e-mail]> wrote in message
news:um******** ******@tk2msftn gp13.phx.gbl...

OK, here is the WIERD thing: The For...Each loop only seems to pick up the EVEN or ODD numbered controls! It skips some of the controls (i.e. the odd ones).... if I rerun the loop about three times, one right after the other,

it will finally pick up all the controls and get rid of them.

I have "an" idea, maybe it's because you are removing a control from the
collection in the loop, for example if you used a For loop and removed
controls without taking away 1 from the final index you would over run and
skip controls in a similar way. Maybe try using an integer controlled for
loop and every time you remove a control take away 1 from the counter and

1 from the final index. I've attached an example, excuse the type checking
code, I know it's bad, also I have added a button to simulate the problem
you are getting at current.

Nick.

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[Jack Spry]

"Cor" <no*@non.com> wrote in message
news:3f******** *************** @reader21.wxs.n l...

Tom,

dim ctl as Control
for each ctl in MyPanel.Control s
if typeof ctl is Label then
ctl.text=""
ctl.visible=Fal se
ctl.Dispose()
end if
next I think that the collections in the for each loop is changed in the the

for each loop
I think that nicer is
For i = Me.Controls.Cou nt To 0 Step -1
Dim ctl As Control
it typeof ctl is Label then
Me.Controls.Rem ove(ctl)
Next
I hope this helps
Cor

It doesn't help when you post bad code that doesn't work, despite your good
intentions.

You also might want to learn when to use While or Do loops instead of
misusing a For loop.

[Cor]

Robert
You are right, just forgot to type.
Thanks for your attention.
Cor

[Jack Spry]

"Scott Meddows" <sc************ ******@tsged.co m> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..

Why don't you just set the labels to nothing? Dispose is called by the GC. All you really have to do it kill your reference to the object. Let the GC take care of the rest.

Because that won't work for controls. Controls are referenced by their
container, so it doesn't matter whether you set all code references to
nothing: the container will still hold a reference until you remove the
control or the container itself.

[Cor]

Jack.
Yes I mistyped the -1 but that can every programmer with a little expirience
see.
Robert was so kind to tell that.

But show that you can do it better, send a good working code in this
situation with the do while loop.
Cor

[Scott Meddows]

Then you'd have to loop through a loop and do the
container.contr ols.remove(Your ForEachLoopCont rol) ?

"Jack Spry" <js***@nospamme rs.com> wrote in message
news:OG******** ******@TK2MSFTN GP12.phx.gbl...

"Scott Meddows" <sc************ ******@tsged.co m> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..

Why don't you just set the labels to nothing? Dispose is called by the

GC.

All you really have to do it kill your reference to the object. Let the

GC

take care of the rest.

Because that won't work for controls. Controls are referenced by their
container, so it doesn't matter whether you set all code references to
nothing: the container will still hold a reference until you remove the
control or the container itself.