Dim dbDocType = New ltsDocTypeScheme(SqlConnectionString)
Dim rsDocType = (From dbDocTypeFields In dbDocType.DocTypes Where _
  dbDocTypeFields.ID = id).FirstOrDefault
rsDocType.Expression = Me.Expression
rsDocType.Name = Me.Name
Try
  dbDocType.SubmitChanges()
Catch ex As Exception
  MessageBox.Show(ex.Message,"Fehler")
Finally
  dbDocType.Connection.Close()
End Try

greetz, Ralf