Question

I have a program written in VB.NET which stops a service that uses file x, modifies x, and restarts the service.

I have modified my code for testing so that it just reads in the file as a string and immediately writes it back out.

Shell("net stop " & SERVICE_NAME, , True)

Dim myReader As System.IO.StreamReader
myReader = My.Computer.FileSystem.OpenTextFileReader(x)
fileString = myReader.ReadToEnd()
myReader.Close()

Dim tempFile As System.IO.StreamWriter
tempFile = My.Computer.FileSystem.OpenTextFileWriter(x, False)
tempFile.Write(fileString)
tempFile.Close()

Shell("net start " & SERVICE_NAME, , True)

The stopping of the service is no problem, and modifying the file is no problem, but when the service starts it stops immediately because, as best I can guess, the file is in use. Even when I try to start the service manually, it stops immediately. However, I found that I can open file x, click save without modifying anything, close the file, and start the service and everything works correctly.

If I comment out the writing part, everything works fine.

Also, the file I’m modifying has a .conf file extension. I don’t know if this is relevant.

Any suggestions on what could be causing this behavior?

Thanks,

B.J.

Answer 1

To avoid the BOM you need to specify an encoding that doesn’t have one, use System.Text.Encoding.Default

My.Computer.FileSystem.WriteAllText("c:\test.txt", fileString, False, System.Text.Encoding.Default)

While that convenience method is nice I still prefer to manually create a FileStream object so I can set the sharing flag ensuring that no one accesses my file until I’m done with it:

    Using FS As New System.IO.FileStream("c:\test.txt", IO.FileMode.Create, IO.FileAccess.Write, IO.FileShare.None)
        Using SW As New System.IO.StreamWriter(FS, System.Text.Encoding.Default)
            SW.WriteLine(fileString)
        End Using
    End Using