Why Workflow Services Storing Their Physical Location In The Xamlx File Is A Very Bad Idea

Just now I was trying to debug a Workflow Service in WF4, that a colleague of mine had created. Strange thing was, even though I set a breakpoint the debugger didn’t stop, it just returned the answer as if I wasn’t debugging at all. In the same projects, I have other Workflow Services, and I hade no problem debugging those (except that debugging workflows is slooow, but that’s beside the point).

I started looking a the Debug output, when this line caught my eye:

Instrumentation for debugger fails.  Reason: Could not find file 'C:\TFS\Butler_WCF\EducationWorkflowServices\AktivitetService.xamlx'

“C:\TFS\..” – hey, that’s not were I keep my project files! We, of course, use a source code repository for our code (TFS, actually), and every developer checks out the project to a location of his or her discretion. I, for example, use “C:\@Projects” as the root folder. My colleague, let’s call her Inger, because that’s her name, uses “C:\TFS". But how would the debugger know that, and try to use her structure, just because she created the file, you might wonder.

So did I. A little investigation came up with this. In the Xamlx file for the Workflow Service, right at the top, I found this little nugget:

Why is the physical location of the xamlx file stored IN the file?

Yes, it is true. WF4 keep the physical location of the Workflow Service Xamlx in an attribute called sad:XamlDebuggerXmlReader.Filename in the Xamlx file itself! Naturally, my first instinct was just to remove the the sad:XamlDebuggerXmlReader.Filename attribute. No luck, debugging didn’t work at all. So I changed the attribute to point to my file, in “C:\@Projects”. And behold – debugging works.

What the were you thinking, Microsoft? Do you actually believe that every developer on a project has the same physical structure on their machines? Or do you think that there is always only one developer on a WF4 project? Do you think it’s a good idea that we have to remember to change the sad:XamlDebuggerXmlReader.Filename attribute every time we need to debug a Workflow Service?

All workflows and no play makes Johan a dull boy. But actually, I think I’ll write a tutorial to Workflow Foundation 4 soon. I’ll call it “how to actually use it”.

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