How to change the service accounts used by TFS 2010

As with many Microsoft products running with specific service accounts, TFS offers an easy way to change the service account it uses or update the account password.

You can do this manually by mucking with application pool identities and database permissions but there's a much easier way using the TFS Administration Console.

Assuming you have the right permissions, fire up the console and click into the Application Tier node; in the Application Tier Summary you'll find two links: Change Account and Reapply Account.

Change Account allows you to change the service account used by the system while Reapply Account allows you to change the password for the currently configured account. You can easily switch from Network Service to a local or domain account (or vice versa) but be sure to grant any local/domain account the Log on as service permission.

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Empty ImageUrl results in empty src and duplicate request

Not exactly a new issue but an empty ASP.NET ImageUrl tripped us up today. In this case there were no visible symptoms but two requests were coming through when Fiddlering the page view: the first initiated by the user and the second initiated by the page itself towards the end of the trace. In development with a debugger attached, this was manifest with Page_Load, CreateChildControls, etc being called twice for no obvious reason.

Because I initially thought I introduced the problem with the control I was working on, I first attempted to convince ASP.NET CreateChildControls was complete; I did so by clearing the Controls collection before unleashing my own code and setting the ChildControlsCreated property true once done. Neither of these tricks had any affect and the Fiddler trace had me convinced something beyond the ASP.NET pipeline and IIS had to be at fault.

That turned out to be the case but ASP.NET was still to blame ;-)

Specifically, we were adding a server-side ASP.NET image control but not initialising its ImageUrl property; the image src was later being set by jQuery at runtime on the client side. As mentioned, there were no visible symptoms of the double request: the image src was set as expected by jQuery and everything appeared okay on the surface. The IE dev toolbar also showed image src as being correctly set and there were no 404s in the mix.

It wasn't until we looked at the raw HTML that our ever-faithful admin extraordinaire noticed the empty src="" attribute. Removing the attribute removed the problem so I can only conclude IE is helpful enough to attempt to interpret a request for an empty image as a request for the parent directory of the current page while parsing the HTML before any Javascript runs. Thanks again, IE!

Notably this problem wasn't reproducible in Firefox or Chrome.

To fix the problem, we first set a default value for the ImageUrl property but that left me feeling dirty since it was still resulting in an unnecessary request. When I realised the server-side Image tag wasn't actually being used for anything server-side anyway, I replaced it with a boring old HTML img tag with no src. Microsoft has other, equally lame workarounds for this if you're interested; note they also don't plan to fix this bug.

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Best Practice List Development in SharePoint

I had the honour of speaking on the subject of best practice SharePoint list development at last weekend’s SharePoint Saturday event held in Perth, Western Australia but I want to take this discussion one step further. I’m therefore creating this post to point to my slide deck from the event and as an index for follow-on, detailed posts about some of the items I had to gloss over. There’s precious little out there, in a single location, on the subject of list development guidelines and I’m hoping to change that. If you want to contribute what you feel is a best practice I’ve missed or challenge one of the practices I do have listed, please comment and join the discussion.

Slides are available here: Best Practices for Developing SharePoint Lists (PowerPoint | PDF)

Here are the two key resources I cite in the presentation:

• Best Practices: Common Coding Issues When Using the SharePoint Object Model 
• Best Practices: Using Disposable Windows SharePoint Services Objects