Guff

Importing a textfile to a typed dataset (failing and resolving)

Mark Dryden — Mon, 28 Jan 2008 11:22:00 GMT

I guess as developers we're used to solving the difficult problems, this task isn't working because of dependancy X, Y and Z - so we code around that, handshake with this and validate the other. But as a developer its always the simple things that catch you out.

For instance, I've spent the last 4 hours messing around with loading a comma delimited textfile into a typed dataset using one dataadapter, do some funky things to it and then upload those records into an SQL Server using an SQLDataAdapter. Sounds easy, and it is - check out this previous post for an example.

So, I coded it up and interestingly it loaded the datarows correctly - but all the fields were NULL! Now things shouldn't be more easier than this - you SELECT the data, it flys into the strongly typed dataset and job done. I then spent my time working backwards through the code, exploring the various problems that might be occuring (tablemapping and that kinda thing). However, the problem was much easier to diagnose - basically, a similar issue came up in the forums with someone using the same code as linked and the answer was...

Change the file extension of the textfile being imported! It turns out that the JET driver has certain restrictions placed upon it, by using a '.txt' extension it was expecting a tab delimited file - by changing the extension to '.csv' everything started working. Check out this MS Support Page on the very subject, where only certain file extensions are supported and are subtlly dealt with in different ways.

HTHs somebody - M

No installed debugger has Just-In-Time debugging enabled.

Mark Dryden — Wed, 31 Jan 2007 16:16:00 GMT

As most developer type bods, debugging problems on deployed software can be an arduous task at best. Sure, tracing and asserts are great tools to be utilised and the JIT Debugger is cracking allowing the debugger to view the call stack as well as a plain text explanation of the unhandled exception. Well, using Framework 1.* that was the case.

However, after deploying a Framework 2.0 application to a Windows XP Home (SP2) machine with all the usual critical patches installed, etc. a nasty little error poked up its impish head. However, rather than showing the usual application crashed type dialogs - it gave the rather cryptic...

<Message> An unhandled win32 exception occurred in >application exe< [1808]. Just-In-Time debugging this exception failed with the following error: No installed debugger has Just-In-Time debugging enabled. In Visual Studio, Just-In-Time debugging can be enabled from Tools/Options/Debugging/Just-In-Time.

Check the documentation index for 'Just-in-time debugging, error' for more information.
</Message>

OK - I thought - I'll install the Framework 2.0 SDK that I assumed would install the appropriate debugger and hey presto. But it didn't.

Searching around I found information that the following key should be added to the app.config file.

<system.windows.forms jitDebugging="true"/>

But that didn't work either.

After an awful lot of searching around, checking the existence of specific registry keys and inserting new ones but again to no avail. Luckily after posting on a newsgroup I was 'seeded' with the answer.

“Install another debugger such as the 'WinDbg' available for free from Microsoft.”

Now to be fair, after wasting the best part of a week attempting to suss this out (albeit I worked out where the error had occurred) I was willing to listen to anything and quite frankly sacrifice any number of domestic animals you care to mention. So to the chase, you can download WinDbg from MS just (http://www.microsoft.com/whdc/devtools/debugging/installx86.mspx).

Once downloaded, install the application.
Once installed, navigate to <Program Files>\Debugging Tools for Windows\ and execute the 'WinDbg' executable with the switch '-I', e.g. from the run command "C:\Program Files\Debugging Tools for Windows\WinDbg -I".

This will install and use the WinDbg application as your default debugger. Now when running an application and it throws an unhandled exception - the new debugger will appear. However, if your life is too short to fumble through the stack and register traces you can load the managed 'sos.dll' file that provides a host of helper functions to specifically debug managed applications. To do this, in the command line window type...

!<DIR>sos.help

Where the <DIR> is the path to the appropriate 'sos.dll' file. For example, to utilise the 'sos.dll' file for Framework 2.0 type "!C:\Windows\Microsoft.NET\Framework\v2.0.50727\sos.help".

Note 1: the debugger application comes with its own 'sos.dll' for Framework 1.1 that is located under the sub-directory of the 'WinDbg' application called 'clr10'.
Note 2: to save having to type the path of the 'sos.dll' file it can be copied to another directory.

After pressing enter, the CLI Window will print all the available commands that this helper library provides. For example, to get a readable version of the exception type...

!pe

...to print the exception that has occurred.

Now to be fair - I haven't a clue why this scenario occurred. Why the SDK JITdebugger didn't invoke? (And I tried this on 3 different machines and reinstalled the OS on each machine at least twice?) Was there some kind of restriction on Windows XP Home or maybe even an MS Update that is preventing some exploit but also causes this issue - who knows?

Anyhoo, if this was useful then drop a line or if you have some killer alternative that doesn't involve gambling in Eastern Europe, enhancing my already perfect physique or purchasing mediation cheaply then drop a comment.

Update : Drydo's on Leicester to Skegness Challenge

Mark Dryden — Wed, 07 Sep 2005 15:09:00 GMT

Well, for those of you who were interested - I did the ride and it wasn't much fun - especially considering the breeze it was last year. Full details just here...

Goddamn Avocados

Mark Dryden — Tue, 30 Nov 2004 13:13:00 GMT

Generally I've never had anything against Avocados and whilst they simply haven't achieved the aspiring heights of say Asparagus - they quietly do their part in a determined and respected way. Some may argue that they do their bit on the Guacamole front or even adding a new twist to Prawn Cocktail - but my support for avocado was literally slashed on Sunday.

Why do they have to have stones that a) serve no purpose (apart from being the seed of another avocado plant) and b) so bloody stubborn that they cannot be removed without welding equipment and are often figures of inspiration to barnacles and other limpet like creatures.

How many times have I watched Jamie Oliver and seen that chubby mockney face in complete honesty remove an Avocado Stone when its quite obvious that its either a) a theatrical avocado or b) someone really hard has loosen it beforehand so he beam 'Pukka' at the camera.

So picture the scene - last Sunday, friends for dinner and Avocados to be peeled, stoned and sliced. Innocently, the memories of so many cookery programmes watched half-arsed flood back to me...

[Slice the Avocado in Half]
Done

[Slight twist the two halves and remove the half without a stone]
OK

[Using the knife, lightly strike the stone with the blade]
With you

[Twist slight and stone will easily come free]
The top (or exposed) half of the stone cracks off

Er. Jamie?

At this point - I decided to improvise. I tried a corkscrew, but this had the effect of chewing up the stone. I tried a spoon, but this messed up the avocado (think of the presentation of dish people). So, I got my trusty knife and tried to gently insert it through the stone so I could flip it out. Feeling a bit of resistance I applied some more pressure and at this point it went all wrong...

The knife sailed through the stone, through the soft fleshy skin of the avocado and into the soft fleshy part of my finger. Now I would hasten to add that this wasn't no mere nick - it went to the bone and lower third of my finger sliced across looking like a hungry Pac-Man like figure. Boy did it hurt.

Anyway, after some messy bandaging and explanations of certain four-letter words to the nipper, I ended up at the hospital for stitches. Which of course is not one of my favourite ways to spend a Sunday afternoon - having some a bored nurse looking down at me, slowly shaking her head thinking "Avocado's.....when will people learn".

No wonder the US banned them...

10 points for inventiveness - Flash CV

Mark Dryden — Fri, 12 Nov 2004 15:49:00 GMT

Just received this linky in the mail.

http://213.186.36.10/~al/alstudio/cv/en.htm

Its a CV done in Flash by a Frenchmen - interesting concept, mildly stylised, but he's still French so Nil Point.