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How can I create a custom exception class in vb.net

I am using vb.net 2003 to create a custom exception handling class. The code that I am currently using works fine but I will need to use this exception handling pages containing data connections, queries, etc. and would like to just access a custom class. Here is a short version of the code that is working and the code snippet attached is what I have in the class so far. The line ex.message.tostring is not working. Any help or direction on how to accomplish this would be appreciated. Thank-you very much.
Try
Catch ex As Exception
'WORKING CODE
'Dim file As New System.IO.StreamWriter(Server.MapPath("..\ErrorLog.txt"), True)
'file.WriteLine(FormatDateTime(Date.Now, DateFormat.GeneralDate))
'file.WriteLine(ex.Message.ToString())
'file.WriteLine(ex.Source.ToString())
'file.WriteLine(ex.StackTrace.ToString())
'file.Close()
'Response.Redirect("http://localhost/NetTestDocs/ErrorsRedirectPage.aspx")
'END OF CODE
Finally
conn.Close()
conn.Dispose()
End Try
End Sub

Public Class ErrorsClass
    Public ex As Exception
    Sub writererror()
        'Dim file As New System.IO.StreamWriter(Server.MapPath("..\ErrorLog.txt"), True)
        Dim file As New System.IO.StreamWriter(HttpContext.Current.Server.MapPath("..\ErrorLog.txt"), True)
        file.WriteLine(FormatDateTime(Date.Now, DateFormat.GeneralDate))
        'file.WriteLine(ex.Message.ToString())
        file.Close()
    End Sub
 
End Class

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InteractiveMind

In the catch block, re-throw your exception, but to your custom class.

An example here:
http://www.vbdotnetheaven.com/UploadFile/susanabraham/CustomExceptionHandlingvb11122005021337AM/CustomExceptionHandlingvb.aspx?ArticleID=4ce8bdfe-1a63-44da-a4a3-f8e796d63302

When you say that ex.Message.ToString() is "not working", do you mean that it's returning an empty string?

If you replace these two lines:

'file.WriteLine(ex.Message.ToString())
'file.WriteLine(ex.Source.ToString())

with

'file.WriteLine(ex.ToString())

does it include the expected message? (Wishful thinking here)

Arthur_Wood

you can also create your own Exception, by crearing a class the inherits from Exception:

Public Class MyException Inherits Exception
   Private _exceptionMessage as String
   Public ReadOnly Property ExceptionMessage() as String
      Property Get
       Return _exceptionMessage 
      End Get
   End property
   Public Sub New(ByVal Message as String)
      MyBase.New("Custom Error")
      _exceptionMessage = Message
   End Sub
 
End Class
 
 
Then you can use it like this:
 
     Try
        If someCondition then
            Throw New MyException("Something dreadful has happened")
        End if
     Catch ex as MyException
          MessageBox.Show(ex.ExceptionMessage, vbOkOnly
     Finally
     End try

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lnshop

ASKER

Thank-you so much for your help. I have the error message working now but I am having a problem adding the error source. Attached is the class code. How can I add the error source to the text file. I have tried adding source as a property and have tried adding innerException and can't get this to work. If you could help me with adding the exception source, I would appreciate it very much.

'CODE IN VB CODE BEHIND
Catch ex As Exception
'REFERENCE TO ERRORS CLASS
Dim myerror As ErrorsClass
myerror = New ErrorsClass(ex.Message)
myerror.writererror()

'ERRORS CLASS
Imports System.Exception
Public Class ErrorsClass
    Inherits Exception
    Private _exceptionMessage As String
    Public ReadOnly Property exceptionMessage() As String
        Get
            Return _exceptionMessage
        End Get
    End Property
    Public Sub writererror()
        Dim file As New System.IO.StreamWriter(HttpContext.Current.Server.MapPath("..\ErrorLog.txt"), True)
        file.WriteLine(FormatDateTime(Date.Now, DateFormat.GeneralDate))
        file.WriteLine(Message.ToString())
        file.Close()
    End Sub
End Class

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ASKER CERTIFIED SOLUTION

Arthur_Wood

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lnshop

ASKER

Thank-you very much. That works great. I have the source and stack trace being written to the error log now.

Arthur_Wood

Glad to be of assistance

AW