ListView problem

[Joza]

Hi!

I'm getting error when selecting items in ListView control, it
says ArguementOutOfR angeExceptions. That happens in SelectIndexChan ge
event. I have tryed with try...catch but there's no effect.
The code inside that event is:

private void LVKalk_Selected IndexChanged(ob ject sender, System.EventArg s e)
{
try
{
txtBox1.Text = LVKalk.Selected Items[0].Text;
txtBox2.Text = LVKalk.Selected Items[0].SubItems[1].Text;
}
catch (ArgumentOutOfR angeException err)
{
err = null;
}
}

What I'm doing wrong?

Thnx.

[Peter Duniho]

Re: ListView problem

On Fri, 11 Apr 2008 14:03:14 -0700, Joza
<josip.pejakovi c@MAKNIOVOetfos .hrwrote:

I'm getting error when selecting items in ListView control, it
says ArguementOutOfR angeExceptions. That happens in SelectIndexChan ge
event. I have tryed with try...catch but there's no effect.
[...]
What I'm doing wrong?

What is it that you want to have happen? What is in your ListView in the
first place?

The exception is telling you that either the SelectedItems collection has
fewer than 1 element (i.e. no elements), or the SubItems collection has
fewer than 2 elements.

The only obvious thing in your code example that's wrong is the line where
you set the "err" variable to null. Since doing so has no effect outside
that block of code, and you don't have any other code inside that block,
whatever it is you expect setting it to null to do, I'm confident it
doesn't do that.

Something wrong that's perhaps less obvious is the assumption in the code
that the SelectedItems collection has at least one element, and that the
SubItems collection has at least two elements. Whether that's a fair
assumption for you to make is hard to say without a complete code
example. But obviously the assumption is wrong.

It seems to me that if you checked the count of elements in each
collection before trying to use them, you would at least have a better
idea of which assumption has failed. It's possible that with that
additional information, it would also be more obvious why your assumption
was incorrect and what you need to do to correct that (either don't make
the assumption, or fix the code that was supposed to ensure the assumption
was correct).

Pete

[Joza]

Re: ListView problem

Peter Duniho wrote:

On Fri, 11 Apr 2008 14:03:14 -0700, Joza
<josip.pejakovi c@MAKNIOVOetfos .hrwrote:
>

>I'm getting error when selecting items in ListView control, it
>says ArguementOutOfR angeExceptions. That happens in SelectIndexChan ge
>event. I have tryed with try...catch but there's no effect.
>[...]
>What I'm doing wrong?

>
What is it that you want to have happen? What is in your ListView in
the first place?
>
The exception is telling you that either the SelectedItems collection
has fewer than 1 element (i.e. no elements), or the SubItems collection
has fewer than 2 elements.
>
The only obvious thing in your code example that's wrong is the line
where you set the "err" variable to null. Since doing so has no effect
outside that block of code, and you don't have any other code inside
that block, whatever it is you expect setting it to null to do, I'm
confident it doesn't do that.
>
Something wrong that's perhaps less obvious is the assumption in the
code that the SelectedItems collection has at least one element, and
that the SubItems collection has at least two elements. Whether that's
a fair assumption for you to make is hard to say without a complete code
example. But obviously the assumption is wrong.
>
It seems to me that if you checked the count of elements in each
collection before trying to use them, you would at least have a better
idea of which assumption has failed. It's possible that with that
additional information, it would also be more obvious why your
assumption was incorrect and what you need to do to correct that (either
don't make the assumption, or fix the code that was supposed to ensure
the assumption was correct).
>
Pete

hm... I'm little bit confused beacuse my listview is populated and it has
several columns and it contains more than one elemnt, but i need to get
only data from first and second column and when i select with mouse sometimes
throws me a message with error that i described early in my first post.
I get this error only when i use SelectItemChang e event,
but if i use Click or DoubleClick events there is no such error, it works fine.

I have changed this part of code
catch (ArgumentOutOfR angeException err)
{
err = null;
}

with this one

catch (Exception ex) {}

And now works fine, but sometimes my program get blocked for second or two
when i selecting items in listview control and after that all works fine
and there is no any type of error messages.

[Peter Duniho]

Re: ListView problem

On Fri, 11 Apr 2008 15:31:00 -0700, Joza
<josip.pejakovi c@MAKNIOVOetfos .hrwrote:

hm... I'm little bit confused beacuse my listview is populated and it has
several columns and it contains more than one elemnt, but i need to get
only data from first and second column and when i select with mouse
sometimes
throws me a message with error that i described early in my first post..

The best way to get unconfused is to find out what's happening. You can
either change the code in the way I suggested, or even better you can just
look at the current state of the data in the debugger when the exception
happens.

Without finding out what's actually happening, you'll remain confused, I'm
afraid. That's just how life is.

I get this error only when i use SelectItemChang e event,
but if i use Click or DoubleClick events there is no such error, it
works fine.

If I had to guess (and so far, looks like I do), I'd say that you're
getting the exception when you click outside a valid item, thus causing no
items to be selected, thus the SelectedItems collection winds up empty,
thus the exception.

For some collection controls, you only get a Click event when an actual
item in the collection was selected. I haven't bothered to check, but
ListView might be one of those controls. In which case, obviously you
won't get notified except when an actual item in the collection is
selected. That would explain why your code fails when you're handling the
SelectedItemCha nged event but not the Click event.

But guessing is no way to write code. It's much better to just look and
see what's going on.

I would do so myself, except you haven't provided a concise-but-complete
code sample with which to do so.

I have changed this part of code
catch (ArgumentOutOfR angeException err)
{
err = null;
}
>
with this one
>
catch (Exception ex) {}

Neither version is an appropriate solution, really. Assuming the
exception being thrown is really the ArgumentOutOfRa ngeException, then
either is equivalent. And neither helps you understand what's wrong or
address it in a more correct way.

And now works fine, but sometimes my program get blocked for second or
two
when i selecting items in listview control and after that all works fine
and there is no any type of error messages.

Well, there are no error messages because you're eating them all. I can't
explain the pause in your program's execution. Exceptions are expensive,
but they aren't _that_ expensive. Unless for some reason you get a huge
number of them all at once.

Still, it's possible that if you wrote the code in a way that didn't
generate exceptions, your problems might go away.

Pete

[=?Utf-8?B?U2FpbXZw?=]

RE: ListView problem

Hello Joza. Good Day.

Try this code.


txtBox1.Text = LVKalk.Items[LVKalk.FocusedI tem.Index].SubItems[0].text;
txtBox2.Text = LVKalk.Items[LVKalk.FocusedI tem.Index].SubItems[1].text;

I hope it can help you.
--
To be Happy is To be Yourself


"Joza" wrote:

Hi!
>
I'm getting error when selecting items in ListView control, it
says ArguementOutOfR angeExceptions. That happens in SelectIndexChan ge
event. I have tryed with try...catch but there's no effect.
The code inside that event is:
>
private void LVKalk_Selected IndexChanged(ob ject sender, System.EventArg s e)
{
try
{
txtBox1.Text = LVKalk.Selected Items[0].Text;
txtBox2.Text = LVKalk.Selected Items[0].SubItems[1].Text;
}
catch (ArgumentOutOfR angeException err)
{
err = null;
}
}
>
What I'm doing wrong?
>
Thnx.
>

[Martin]

Re: ListView problem

On Apr 12, 3:21 am, Saimvp <Sai...@discuss ions.microsoft. comwrote:

Hello Joza. Good Day.
>
Try this code.
>
txtBox1.Text = LVKalk.Items[LVKalk.FocusedI tem.Index].SubItems[0].text;
txtBox2.Text = LVKalk.Items[LVKalk.FocusedI tem.Index].SubItems[1].text;
>
I hope it can help you.
--
To be Happy is To be Yourself
>
>
>
"Joza" wrote:

Hi!

>

I'm getting error when selecting items in ListView control, it
says ArguementOutOfR angeExceptions. That happens in SelectIndexChan ge
event. I have tryed with try...catch but there's no effect.
The code inside that event is:

>

private void LVKalk_Selected IndexChanged(ob ject sender, System.EventArg se)
{
try
{
txtBox1.Text = LVKalk.Selected Items[0].Text;
txtBox2.Text = LVKalk.Selected Items[0].SubItems[1].Text;
}
catch (ArgumentOutOfR angeException err)
{
err = null;
}
}

>

What I'm doing wrong?

>

Thnx.- Hide quoted text -

>
- Show quoted text -

The event will be triggered when the selection changes from one, or
several, to none, just as Peter Duniho said. So what you need to do is
to ensure that at least one item is selected. I would use the
following code to make sure of that. It's also good practice to try to
avoid throwing exceptions.

if (LVKarl.Selecte dItems.Count 0)
{
...
}