This is preaty handy for catching page errors and writing them down in log file which is automaticaly deleted if he reaches defined file size.

Imports System.IO



Public Shared Sub PageErr(ByVal ErrorMessage As String, ByVal UserIPAddress As String, _
ByVal URLRefferer As String, ByVal PathToLogFile As String, _

ByVal FileMaxSize As Integer, ByVal FileName As String)
Dim fileExists As Boolean = My.Computer.FileSystem.FileExists(PathToLogFile & FileName)

If fileExists = False Then

Try

My.Computer.FileSystem.WriteAllText(PathToLogFile & FileName, "File created: " & DateTime.Now.ToString, False)
My.Computer.FileSystem.WriteAllText(PathToLogFile & FileName, _

vbCrLf & vbCrLf & "/**************************** " & DateTime.Now.ToString & " ********************************/" & _
vbCrLf & "Error level: Page level" & _

vbCrLf & "Error message: " & ErrorMessage & _
vbCrLf & "URL refferer: " & URLRefferer & _

vbCrLf & "Users' IP: " & UserIPAddress, True)
Catch ex As Exception

End Try

Else

Dim fileSize As Long = My.Computer.FileSystem.GetFileInfo(PathToLogFile & FileName).Length()
If fileSize >= FileMaxSize Then

Try

My.Computer.FileSystem.DeleteFile(PathToLogFile & FileName, FileIO.UIOption.OnlyErrorDialogs, FileIO.RecycleOption.DeletePermanently)
My.Computer.FileSystem.WriteAllText(PathToLogFile & FileName, "File created: " & DateTime.Now.ToString, False)

My.Computer.FileSystem.WriteAllText(PathToLogFile & FileName, _
vbCrLf & vbCrLf & "/**************************** " & DateTime.Now.ToString & " ********************************/" & _

vbCrLf & "Error level: Page level" & _
vbCrLf & "Error message: " & ErrorMessage & _

vbCrLf & "URL refferer: " & URLRefferer & _
vbCrLf & "Users' IP: " & UserIPAddress, True)

Catch ex As Exception
End Try

Else

My.Computer.FileSystem.WriteAllText(PathToLogFile & FileName, _
vbCrLf & vbCrLf & "/**************************** " & DateTime.Now.ToString & " ********************************/" & _

vbCrLf & "Error level: Page level" & _
vbCrLf & "Error message: " & ErrorMessage & _

vbCrLf & "URL refferer: " & URLRefferer & _
vbCrLf & "Users' IP: " & UserIPAddress, True)

End If

End If

End Sub



Just pass the aguments and make sure that aspnet user has apropriate read write permissions over the folder where you are going to store the log file

Hope it helps