vb.net 2010 streamwriter

Patricia Kolb

I have a subroutine called 'ErrorFileProcess'. It takes in my error number, error message, and error file name which includes path, and writes that error message to the error file. The sub 1st determines if the file already exists, and if so, opens with append, otherwise it creates the file. When I first call the subroutine it works just fine, sees that there is NO error file so it creates it and writes out the error. But when I call the routine again, it correctly sees that the file DOES exist, but when I try to open it for append the program errors and says that the file is locked by another process.

ex.Message is: The process cannot access the file '\\ffgenv\docenv\FFG\DPBatch_Error.Log' because it is being used by another process.
Below is the code:

Public Sub ErrorFileProcess(ByVal strErrData As String, ByVal intMyErrNum As Integer, ByVal strFileNamePath As String)
blnErrorHit = True
Dim strErrBeginText As String
Try
If System.IO.File.Exists(strFileNamePath) = True Then

Using writer As StreamWriter = New StreamWriter(strFileNamePath, True)
writer.WriteLine("Err Msg: " & strErrData & " Err Num: " & intMyErrNum)
writer.Close()
End Using

Else

Using writer As StreamWriter = New StreamWriter(strFileNamePath)

strErrBeginText = "DocPrint Batch ERROR Report" & vbCrLf
writer.WriteLine(strErrBeginText)
strErrBeginText = "Date Time Created: " & System.DateTime.Now & vbCrLf & vbCrLf
writer.WriteLine(strErrBeginText)
strErrBeginText = "ERROR MESSAGE" & vbCrLf
writer.WriteLine(strErrBeginText)
writer.WriteLine("Err Msg: " & strErrData & " Err Num: " & intMyErrNum)
writer.Close()

End Using

End If
Catch ex As Exception

ErrorEmail("Exception from ErrorFileProcess where ex.Message is: " & ex.Message) 'this is the error module, its the end of the line, so all I can think to do is send email at this point

End Try

9 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes14y ago
Accepted answer
Why don't you copy the file and then attach the copy to the email.

That way the original will still be available to write to.
George Gilbert14y ago
Roger that. Good call.
Vulpes14y ago
I think the problem here, George, was that the file was locked when it was attached to the email.

When Patricia copied it and attached the copy, the error went away.
George Gilbert14y ago
Sounds logical; however, the code is apparently not performing that way. Adding a .Dispose after each streamreader/writer .Close has, for me, always eliminated the file in use error regardless of where the code resides.
Vulpes14y ago
As Patricia has put the StreamWriter in a Using statement, Dispose will be called anyway when the Using statement ends.
George Gilbert14y ago
I've run into this apparent contradiction before with streamreader and streamwriter. The simple solution is to add .Dispose after each .Close. The .Dispose releases the file.
Patricia Kolb14y ago
Thank you for your help. We are back on track.
Patricia Kolb14y ago
Based on some error types, I do call a routine that sends an email using System.Net.Mail, but that is all. It attaches the error file as it is at that point using the following. I removed all of my calls to the email sub and do not get the error. Does this mean that you can never send a file via email and then ever write to it again within that program once you've emailed it? Thank you for your help.

Dim msg1.Attachments.Add(myAttachment)
myAttachment As Net.Mail.Attachment = New Net.Mail.Attachment(strFileName)
Vulpes14y ago
The code looks fine to me, the main thing being that you're closing the stream (and hence the file) after writing to it.

Are you sure that after the initial write you're not opening the file in some other program, which is the only reason I can think of why you'd get this exception?