[VB.NET 2008] DataSet and XML files

steve_9496613

Hi, in my application (running in Windows CE) I use a XML file to store some configuration data that, at runtime, I load in a DataSet. To read and to store these data I use the following code:

Private Shared Function SetCfgData() As Boolean

Try
  Dim fs As New FileStream(CGlobali.CfgDataFileComplName, FileMode.Open)
  Dim xr As XmlReader = System.Xml.XmlReader.Create(fs)

  'CGlobali.CfgData is a DataSet
  CGlobali.CfgData.Clear()
  CGlobali.CfgData.ReadXml(xr)

  xr.Close()
  fs.Close()

Catch ex As System.IO.FileNotFoundException
  MessageBox.Show("File " & CGlobali.CfgDataFileComplName & " not found.")
  Return False
Catch ex As XmlException
  MessageBox.Show("XmlException occured: " & ex.ToString)
  Return False
End Try

Return True

When the user modifies these data, they are automatically updated in the DataSet and saved in the file, at least that's what I would do... To save the data from the DataSet to the file I do this:

Private Shared Function UpdateCgfFile() As Boolean

Try
  Dim StreamEncoding As Encoding
  StreamEncoding = Encoding.Unicode
  Dim cfgfile As New System.IO.StreamWriter(CGlobali.CfgDataFileComplName, True, StreamEncoding)

  CGlobali.CfgData.WriteXml(cfgfile)

  cfgfile.Close()

  Return True
Catch ex As Exception
  Return False
End Try

End Function

What I would get with the above code is to update existing fields in the xml file with the new values, but what I get is that the same fields are added to the existing ones. This is the "original" file:

and this is the file after a save:

10.0.0.85
502

15000
5000
5000


192.168.1.10
502
15000
5000
5000

Obviously this is not the result I want to achieve, I do not want to du

Lost User

steve_9496613 wrote:

Can someone tell me what I'm doing wrong?

Dim cfgfile As New System.IO.StreamWriter(CGlobali.CfgDataFileComplName, True, StreamEncoding)

What does the second parameter in the StreamWriter do?

MSDN[^] states:

true to append data to the file; false to overwrite the file. If the specified file does not exist, this parameter has no effect, and the constructor creates a new file.

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^] They hate us for our freedom![^]

steve_9496613

...ops... :sigh: ...next time I'll be more careful... Thanks Eddy

Lost User

You're welcome :)