Application global Error Logger

Question

Hi all,

While working on a vb.net application, in which exceptions were handled poorly. It was a big pain. So an Idea flashed , that if it is possible to genearte a library or service or some sort of exe that will log all error of an application without writing a single line of code / minimal code at some global location in host application. I know it sounds bit crazy but Windows Event Logger does the same. So i thought for the same. Let me make me more clear. Say I have an application abc.exe, with not a single try catch. I am facing lots of bug while using that app. Now instead of digging my head into the application source, I want to code another app that will run and log all unhandled exceptions of that app, including managed and com both.

So gurus are requested to help me out. I know ApplicationDomain is useful. I came across a guy name Rick or something similar over MSDN blog but i did'nt grab any more. So some easy source or part of code will be helpful. Please add some sample code with your answers.

It would be a great help.

SUMMARY

I want a application that will inject itself into any application , where the assembly of Injector is placed. That is If i have an application D:\xyz\myapp\abc.exe , if say i had the application as exe then if place it inside myapp folder then after the execution of abc.exe , universal my error logger application will start working and inject itself to the current application domain. Also tell me if it will be made multi threaded , if i create it as a service.

Answer 1

If I understand correctly, you do have the source of the application with the bad error handling and you'd be able to amend it and re-compile it.

If so, you might want to look at the AppDomain.UnhandledException Event. Quote from MSDN: This event provides notification of uncaught exceptions. It allows the application to log information about the exception before the system default handler reports the exception to the user and terminates the application.

If you go to the link there's a sample for the code you need to add, and it's just a few lines of code that can all go in one file in your app so should be easy enough to add.

Answer 2

This MSDN page How to: Log Exceptions in Visual Basic exactly describes what you need. In summary, it describes:

• How to use the Visual Basic My.Application.Log to log exceptions using .NET's built in trace listeners.
• How to register the UnhandledException Forms Application event in VB applications.
• How to register Visual Basic's FileLogTraceListener to log to the file "[User]\Application Data\[CompanyName]\[ProductName]\[ProductVersion][ApplicationName].log".

Here's an example of an application file configuration that registers the VB FileLogTraceListener:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <system.diagnostics>
        <sources>
            <source name="DefaultSource" switchName="DefaultSwitch">
                <listeners>
                    <add name="FileLog"/>
                </listeners>
            </source>
        </sources>
        <switches>
            <add name="DefaultSwitch" value="Information" />
        </switches>
        <sharedListeners>
            <add name="FileLog"
                type="Microsoft.VisualBasic.Logging.FileLogTraceListener, Microsoft.VisualBasic, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL" 
                initializeData="FileLogWriter" />
        </sharedListeners>
    </system.diagnostics>
</configuration>