System.Net.WebException

[tuzojazz]

Hi:

I'm writing an application which downolads a file from a remote server by FTP

this is my code

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Dim ftpURI As String = "ftp://205.134.48.217/"
Try
Dim filename As String = ftpURI & "Digital/sounds/SOUND0608191550.WAV"
Dim client As New WebClient()
client.Credentials = New NetworkCredential("user1", "password1")
My.Computer.FileSystem.WriteAllBytes("C:\hello\SOUND0608191550.WAV", client.DownloadData(filename), False)
MsgBox("File downloaded!")
Catch ex As Exception
MsgBox(ex.ToString)
End Try

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I get an "System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive" most of times at client.DownloadData function but other times it works well.

The size of SOUND0608191550.WAV is 5 MB.

When I try to download a smaller file (1 KB) from the remote server the application works successfully.

When I try to download SOUND0608191550.WAV from a local server the application works successfully too.

What could be wrong?

I suppose the problem is the bandwidth and/or the time out and this is the reason why the application sometimes works and other does not.

do I need to setup something on the server or my PC?

Thanks!!

 

[PsychoCoder]

tuzojazz,

This is due to a known .Net issue where the connection is closed before the request is complete. Essentially requests are made by opening a connection, making a number of them then closing it. In this occurrence, the connection times out but is not recognized as closed and thus a new connection is not established for the next request and an error is returned. Try chaning your code to

Dim ftpURI As String = "ftp://205.134.48.217/"
 Try
     Dim filename As String = ftpURI & "Digital/sounds/SOUND0608191550.WAV"
     Dim client As New WebClient()
     client.Credentials = New NetworkCredential("user1", "password1")
     client.KeepAlive = false
     client.ProtocolVersion=HttpVersion.Version10
      My.Computer.FileSystem.WriteAllBytes("C:\hello\SOUND0608191550.WAV",  client.DownloadData(filename), False)
     MsgBox("File downloaded!")
 Catch ex As Exception
     MsgBox(ex.ToString)
 End Try

and see if that solves your issue.

Senior Qik III, ASP.Net, VB.Net ,SQL Programmer

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[tuzojazz]

Thanks PsychoCoder but I get 2 errors

'KeepAlive' is not a member of 'System.Net.WebClient'
'ProtocolVersion' is not a member of 'System.Net.WebClient'

What could be wrong?

 

[PsychoCoder]

tuzojazz,

What version of .Net are you using because those 2 are members of 2.0

Senior Qik III, ASP.Net, VB.Net ,SQL Programmer

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SELECT * FROM Users WHERE clue > 0
0 Rows Returned

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