Solved

.NET application just closing randomly, event viewer shows P9 system.nullreferenceexception

Posted on 2008-10-19
7
841 Views
Last Modified: 2008-11-02
I've been having random crashes in my application lately... I can't seem to pinpoint what is going on. The application just closes.

Event Viewer shows:

EventType clr20r3, P1 y3stand.exe, P2 1.0.0.0, P3 48f82eb0, P4 system, P5 2.0.0.0, P6 471ebf0d, P7 2c3a, P8 c, P9 system.nullreferenceexception, P10 NIL.

I've added this to the main Form

    Public Event UnhandledException As UnhandledExceptionEventHandler

    Sub Main()
        Dim currentDomain As AppDomain = AppDomain.CurrentDomain
        AddHandler currentDomain.UnhandledException, AddressOf MyHandler
    End Sub

    Sub MyHandler(ByVal sender As Object, ByVal args As UnhandledExceptionEventArgs)
        Dim e As Exception = DirectCast(args.ExceptionObject, Exception)
        Debug.WriteLine("MyHandler caught : " + e.Message)
        LogError2("MyHandler caught : " + e.Message)
    End Sub


LogError2 function opens an httprequest to record the message in my database with a tiemstamp, etc.


Apparently this unhandledexception wasn't caught by this handler... did I do something wrong? How do you guys suggest I locate / handle this?


0
Comment
Question by:mcainc
  • 5
7 Comments
 
LVL 47

Accepted Solution

by:
Wayne Taylor (webtubbs) earned 500 total points
ID: 22753790
If you are using .Net 2.0, you can use the Application events, which contains an UnhandledException event.

Go to your project properties, then in the "Application" tab, click the "View Application Events" button, then paste the below routine in the MyApplication class.

Wayne
        Private Sub MyApplication_UnhandledException(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.ApplicationServices.UnhandledExceptionEventArgs) Handles Me.UnhandledException
            Debug.WriteLine("MyHandler caught : " + e.Exception.Message)
            LogError2("MyHandler caught : " + e.Exception.Message)
        End Sub

Open in new window

0
 

Author Comment

by:mcainc
ID: 22753805
awesome, thanks i will try this
0
 

Author Comment

by:mcainc
ID: 22754521
hmm, it still didn't catch it... the app just closed

event viewer showed this:

EventType clr20r3, P1 y3stand.exe, P2 1.0.0.0, P3 48fba928, P4 system, P5 2.0.0.0, P6 471ebf0d, P7 2c3a, P8 c, P9 system.nullreferenceexception, P10 NIL.

there is some threading in the application, would this cause it?

there is also an external control / dll that is used occasionally, i'm starting to think this might be it, what do you think?

Delcare Function EncryptGrp Lib "C:\EncGrp3.dll" .....

is there any way to catch / contain these errors?

0
Master Your Team's Linux and Cloud Stack!

The average business loses $13.5M per year to ineffective training (per 1,000 employees). Keep ahead of the competition and combine in-person quality with online cost and flexibility by training with Linux Academy.

 

Author Comment

by:mcainc
ID: 22754592
is there a decent free debugging software i can use to load the process & keep an eye on it?

0
 
LVL 1

Expert Comment

by:Abh4IT
ID: 22756541
Not able to identify when it crashes. Is it during inactivity or during some activity it crashes. If it sits idle and crashes, do you have any timer based implementation that restarts at some particular intervals. Can you be a litte more detail of what and how it is happening, so that we can help? Somewhere in your code a codepart is hit with an object coming as null. Before you operate on certain objects you should have the check if object is null. for example fileobjects..
0
 

Author Comment

by:mcainc
ID: 22760551
I do believe it is happening somewhere in a timer

I'll try to add some object checking as you suggested
0
 

Author Comment

by:mcainc
ID: 22764761
im doing some testing now after adding some checking for all of the objects

is there a reason that application events didn't catch this error though? i was under the impression that it would catch any unhanded exceptions
0

Featured Post

Master Your Team's Linux and Cloud Stack

Come see why top tech companies like Mailchimp and Media Temple use Linux Academy to build their employee training programs.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

The object model of .Net can be overwhelming at times – so overwhelming that quite trivial tasks often take hours of research. In this case, the task at hand was to populate the datagrid from SQL Server database in Visual Studio 2008 Windows applica…
More often than not, we developers are confronted with a need: a need to make some kind of magic happen via code. Whether it is for a client, for the boss, or for our own personal projects, the need must be satisfied. Most of the time, the Framework…
Two types of users will appreciate AOMEI Backupper Pro: 1 - Those with PCIe drives (and haven't found cloning software that works on them). 2 - Those who want a fast clone of their boot drive (no re-boots needed) and it can clone your drive wh…
Email security requires an ever evolving service that stays up to date with counter-evolving threats. The Email Laundry perform Research and Development to ensure their email security service evolves faster than cyber criminals. We apply our Threat…

776 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question