An exception occurred during a WebClient request.

[R4PM0NK3Y]

In my application, I am using a web client to download a file to the user's local machine. This works the first time, but after re-downloading I OCCASIONALLY recieve this run-time error:

 

*****************START***********************

An unhandled exception has occurred in a component in your application. Click continue and application will ignore this error and attempt to continue.

 

An exception occurred during a WebClient request.

 

See the end of this message for details on invoking

just-in-time (JIT) debugging instead of this dialog box.

 

************** Exception Text **************

System.Net.WebException: An exception occurred during a WebClient request. ---> System.IO.IOException: The process cannot access the file "c:\Weather Bar\current.wbd" because it is being used by another process.

at System.IO.__Error.WinIOError(Int32 errorCode, String str)

at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, Boolean useAsync, String msgPath, Boolean bFromProxy)

at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access)

at System.Net.WebClient.DownloadFile(String address, String fileName)

--- End of inner exception stack trace ---

at System.Net.WebClient.DownloadFile(String address, String fileName)

at Weather_Bar.frmWeatherBar.GetCurrentWeather() in C:\CMPSC 115\Weather Bar\WeatherBar.vb:line 571

at Weather_Bar.frmWeatherBar.WeatherTimer_Tick(Object sender, EventArgs e) in C:\CMPSC 115\Weather Bar\WeatherBar.vb:line 679

at System.Windows.Forms.Timer.OnTick(EventArgs e)

at System.Windows.Forms.Timer.Callback(IntPtr hWnd, Int32 msg, IntPtr idEvent, IntPtr dwTime)

 

 

************** Loaded Assemblies **************

mscorlib

Assembly Version: 1.0.5000.0

Win32 Version: 1.1.4322.573

CodeBase: file:///c:/windows/microsoft.net/framework/v1.1.4322/mscorlib.dll

----------------------------------------

Weather Bar

Assembly Version: 1.0.1439.34951

Win32 Version: 1.0.1439.34951

CodeBase: file:///C:/CMPSC%20115/Weather%20Bar/bin/Weather%20Bar.exe

----------------------------------------

System.Windows.Forms

Assembly Version: 1.0.5000.0

Win32 Version: 1.1.4322.573

CodeBase: file:///c:/windows/assembly/gac/system.windows.forms/1.0.5000.0__b77a5c561934e089/system.windows.forms.dll

----------------------------------------

System

Assembly Version: 1.0.5000.0

Win32 Version: 1.1.4322.573

CodeBase: file:///c:/windows/assembly/gac/system/1.0.5000.0__b77a5c561934e089/system.dll

----------------------------------------

System.Drawing

Assembly Version: 1.0.5000.0

Win32 Version: 1.1.4322.573

CodeBase: file:///c:/windows/assembly/gac/system.drawing/1.0.5000.0__b03f5f7f11d50a3a/system.drawing.dll

----------------------------------------

System.Xml

Assembly Version: 1.0.5000.0

Win32 Version: 1.1.4322.573

CodeBase: file:///c:/windows/assembly/gac/system.xml/1.0.5000.0__b77a5c561934e089/system.xml.dll

----------------------------------------

Microsoft.VisualBasic

Assembly Version: 7.0.5000.0

Win32 Version: 7.10.3052.4

CodeBase: file:///c:/windows/assembly/gac/microsoft.visualbasic/7.0.5000.0__b03f5f7f11d50a3a/microsoft.visualbasic.dll

----------------------------------------

 

************** JIT Debugging **************

To enable just in time (JIT) debugging, the config file for this

application or machine (machine.config) must have the

jitDebugging value set in the system.windows.forms section.

The application must also be compiled with debugging

enabled.

 

For example:

 

<configuration>

<system.windows.forms jitDebugging="true" />

</configuration>

 

When JIT debugging is enabled, any unhandled exception

will be sent to the JIT debugger registered on the machine

rather than being handled by this dialog.

************************END*******************

 

The code I am using for this is below:

 

Dim wc As New System.Net.WebClient      'Class level variable
wc.DownloadFile("http://www.filename.com/file.html", "c:\File\file.html")

 

What is happening? It says it is being used by another process, but it is not. How can I prevent this error? Thanks in advance!

[Robby]

The first thing you can do is handle the exception by placing your code in a Try/Catch block.

wc.Dispose() 'once you're done

'and if you're using a StreamReader then close it when you're done...

sr.Close()

[R4PM0NK3Y]

I am only using the code posted above. It does NOT work with OR without wc.Dispose().

[Robby]

Well looking at the error message it states that access to "current.wbd" is denied.

 

Is the file open?

And have placed your code in a Try/Catch block?

[R4PM0NK3Y]

Well looking at the error message it states that access to "current.wbd" is denied.

 

Is the file open?

And have placed your code in a Try/Catch block?

 

After looking over the code, it appears the file was open. After closing the file in the right spot, I still get the error... And what is a Try/Catch block?

[R4PM0NK3Y]

Anybody have any suggestions? :)