Binaryworld - AppException - An extended Exception class that logs the errors to fil ... [ ASP.net -> General ]

' This class extends the base Exception class with a static method (callable
' also without creating and throwing an instance of this exception class) to
' log the contents of the exception to a file.

' Notes:
' A custom key named ErrorLogFile must be added to the <appSettings> section,
' within the <configuration> section, to specify the path of the log file,
' as follows:
'  <appSettings>
'    <add key="ErrorLogFile" value="~/ErrorLog.txt" />
'  </appSettings>

' Usage: Throw New WebModules.AppException("This error message will be saved to
' file")

Imports System
Imports System.Web
Imports System.Diagnostics

Namespace WebModules

' Default exception to be thrown by the website, it will automatically
' log the contents of the exception to a file.
' ---
Public Class AppException
  Inherits System.Exception

  ' Constructors
  '- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  Public Sub New()
   LogError("An unexpected error occurred.")
  End Sub

  Public Sub New(ByVal message As String)
   LogError(message)
  End Sub

  Public Sub New( ByVal message As String, ByVal innerException As Exception)

   LogError(message)

   If Not (innerException Is Nothing) Then
    LogError(innerException.Message.ToString)
   End If

  End Sub

  ' Shared Methods
  '- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  Public Shared Sub LogError(ByVal message As String)

   ' Get the current HTTPContext
   Dim context As HttpContext = HttpContext.Current

   ' Get location of ErrorLogFile from Web.config file
   Dim filePath As String = context.Server.MapPath( CStr _
     (System.Configuration.ConfigurationSettings.AppSettings( _
     "ErrorLogFile")))

   ' Calculate GMT offset
   Dim gmtOffset As Integer = DateTime.Compare(DateTime.Now, DateTime.UtcNow)

   Dim gmtPrefix As String
   If gmtOffset > 0 Then
    gmtPrefix = "+"
   Else
    gmtPrefix = ""
   End If

   ' Create DateTime string
   Dim errorDateTime As String = DateTime.Now.Year.ToString & "." & _
     DateTime.Now.Month.ToString & "." & DateTime.Now.Day.ToString & " @ " _
     & DateTime.Now.Hour.ToString & ":" & DateTime.Now.Minute.ToString & _
     ":" & DateTime.Now.Second.ToString & " (GMT " & gmtPrefix & _
     gmtOffset.ToString & ")"

   ' Write message to error file
   Try
    Dim sw As New System.IO.StreamWriter(filePath, True)
    sw.WriteLine("## " & errorDateTime & " ## " & message & " ##")
    'sw.WriteLine(message)
    'sw.WriteLine()
    sw.Close()
   Catch
    ' If error writing to file, simply continue
   End Try

  End Sub

End Class

End Namespace