Can't figure out problem

[James Park]

I'm trying to delete off a 0-byte file that gets created after trying to
download from a bad URL, but I'm getting an IOException that says that it's
being used. I also noticed an InvalidOperationException before the
IOException in the debug output, but I can't seem to try/catch where that
comes up. After stripping off excess code from my .NET 2.0 Windows Forms
app, I have a button, a BackgroundWorker, and a WebClient-inheriting class
(Downloader). What am I doing wrong here?

My code looks like this:
*** Form1 class variables ***
bool myIsDownloading;

*** Form1::button1_Click ***
button1->Enabled = false;
backgroundWorker1->RunWorkerAsync();

*** Form1::backgroundWorker1_DoWork ***
Downloader^ dlr = gcnew Downloader(worker);
String^ filename = "C:\\test.txt";
dlr->DownloadFileAsync(gcnew Uri("crap", UriKind::Relative), filename);
myIsDownloading = true;
while (myIsDownloading)
{
Threading::Thread::Sleep(200);
}
try
{
File::Delete(filename);
}
catch (IOException^ e)
{
// "The process cannot access the file 'C:\\test.txt'
// because it is being used by another process."
// Huh?
MessageBox::Show(e->Message);
}
worker->ReportProgress(100);

*** Form1::backgroundWorker1_ProgressChanged ***
if (e->ProgressPercentage == 50)
{
myIsDownloading = false;
}
else if (e->ProgressPercentage == 100)
{
button1->Enabled = true;
}

*** Downloader::Downloader(BackgroundWorker^ bw) ***
myBackgroundWorker = bw;

*** Downloader::OnDownloadFileCompleted ***
myBackgroundWorker->ReportProgress(50);

[Vladimir Nesterovsky]

> I'm trying to delete off a 0-byte file that gets created after trying to

download from a bad URL, but I'm getting an IOException that says that it's being used. I also noticed an InvalidOperationException before the
IOException in the debug output, but I can't seem to try/catch where that
comes up.
You can configure debugger to break on exceptions (Debug/Exception). Say C++
and CLR exceptions. This way you will now where InvalidOperationException
comes from.
After stripping off excess code from my .NET 2.0 Windows Forms
app, I have a button, a BackgroundWorker, and a WebClient-inheriting class
(Downloader). What am I doing wrong here?

--
Vladimir Nesterovsky
e-mail: vl******@nesterovsky-bros.com
home: http://www.nesterovsky-bros.com

[James Park]

Thanks, that helped me track down the problem. I used a relative Uri for my
test on the DownloadFileAsync method without setting the BaseAddress
property for the WebClient. But why doesn't a try/catch block around that
call catch that exception?

"Vladimir Nesterovsky" <vl******@nesterovsky-bros.com> wrote in message
news:OS**************@tk2msftngp13.phx.gbl...

I'm trying to delete off a 0-byte file that gets created after trying to
download from a bad URL, but I'm getting an IOException that says that

it's

being used. I also noticed an InvalidOperationException before the
IOException in the debug output, but I can't seem to try/catch where that
comes up.

You can configure debugger to break on exceptions (Debug/Exception). Say
C++
and CLR exceptions. This way you will now where InvalidOperationException
comes from.

After stripping off excess code from my .NET 2.0 Windows Forms
app, I have a button, a BackgroundWorker, and a WebClient-inheriting
class
(Downloader). What am I doing wrong here?

--
Vladimir Nesterovsky
e-mail: vl******@nesterovsky-bros.com
home: http://www.nesterovsky-bros.com

[Severian [MVP]]

On Sat, 25 Jun 2005 00:14:57 -0700, "James Park"
<jp**********@SpaMMEhotmail.com> wrote:

Thanks, that helped me track down the problem. I used a relative Uri for my
test on the DownloadFileAsync method without setting the BaseAddress
property for the WebClient. But why doesn't a try/catch block around that
call catch that exception?
Don't know if it is exactly the answer to your question, but
exceptions can only be caught in the thread from which they originate.
(For example, ActiveMovie exceptions cannot usually be caught, since
AM usually starts multiple threads.)

"Vladimir Nesterovsky" <vl******@nesterovsky-bros.com> wrote in message
news:OS**************@tk2msftngp13.phx.gbl...

I'm trying to delete off a 0-byte file that gets created after trying to
download from a bad URL, but I'm getting an IOException that says that

it's

being used. I also noticed an InvalidOperationException before the
IOException in the debug output, but I can't seem to try/catch where that
comes up.

You can configure debugger to break on exceptions (Debug/Exception). Say
C++
and CLR exceptions. This way you will now where InvalidOperationException
comes from.

After stripping off excess code from my .NET 2.0 Windows Forms
app, I have a button, a BackgroundWorker, and a WebClient-inheriting
class
(Downloader). What am I doing wrong here?

--
Vladimir Nesterovsky
e-mail: vl******@nesterovsky-bros.com
home: http://www.nesterovsky-bros.com

--
Phillip Crews aka Severian
Microsoft MVP, Windows SDK
Posting email address is real, but please post replies on the newsgroup.

[James Park]

Ah, that makes sense. Thanks.
"Severian [MVP]" <se******@chlamydia-is-not-a-flower.com> wrote in message
news:3r********************************@4ax.com...

On Sat, 25 Jun 2005 00:14:57 -0700, "James Park"
<jp**********@SpaMMEhotmail.com> wrote:

Thanks, that helped me track down the problem. I used a relative Uri for
my
test on the DownloadFileAsync method without setting the BaseAddress
property for the WebClient. But why doesn't a try/catch block around that
call catch that exception?

Don't know if it is exactly the answer to your question, but
exceptions can only be caught in the thread from which they originate.
(For example, ActiveMovie exceptions cannot usually be caught, since
AM usually starts multiple threads.)

"Vladimir Nesterovsky" <vl******@nesterovsky-bros.com> wrote in message
news:OS**************@tk2msftngp13.phx.gbl...

I'm trying to delete off a 0-byte file that gets created after trying
to
download from a bad URL, but I'm getting an IOException that says that
it's
being used. I also noticed an InvalidOperationException before the
IOException in the debug output, but I can't seem to try/catch where
that
comes up.

You can configure debugger to break on exceptions (Debug/Exception). Say
C++
and CLR exceptions. This way you will now where
InvalidOperationException
comes from.

After stripping off excess code from my .NET 2.0 Windows Forms
app, I have a button, a BackgroundWorker, and a WebClient-inheriting
class
(Downloader). What am I doing wrong here?

--
Vladimir Nesterovsky
e-mail: vl******@nesterovsky-bros.com
home: http://www.nesterovsky-bros.com

--
Phillip Crews aka Severian
Microsoft MVP, Windows SDK
Posting email address is real, but please post replies on the newsgroup.