Recently, I started developing new applications around the Umbraco Content Management System. I use the term around very lightly, because Umbraco really doesn't require any constraints on your code (like DNN, Rainbow and virtually every other .Net based CMS that I have used), other than the need to develop in user controls instead of aspx pages - which makes perfect sense given the idea of a CMS. It has worked flawlessly and is easily the best .net based CMS system around from a developer AND designer perspective.

I ran into my first hiccup yesterday when trying to develop using AJAX in Umbraco. My design project had been setup to target the 3.5 extensions, while Umbraco is generally configured to use the 2.0 version with the AJAX extensions. All is well with controls, until trying to use AJAX - apparently enough changed under the hood to require a dependency for the version of the ScriptManager and UpdatePanel being used.

The Umbraco community came to the rescue before the ink was dry on my forum post. The initial reply to my issue came within a few minutes on the public Umbraco forums [My Post] and while their first suggestions didn't fix the problem, it certainly led me in the right direction and on to the final solution: http://forum.umbraco.org/yaf_postst1245_A-version-compatible-with-Windows-Server-2008--ASPNET-35.aspx

BTW - all it takes to get Umbraco to start using the 3.5 extensions is the following addition to your web.config:

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Extensions" publicKeyToken="31bf3856ad364e35"/>
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Extensions.Design" publicKeyToken="31bf3856ad364e35"/>
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>

Just before your closing <\configuration> tag.

Thanks to Doug Robar, Sjors Pals, Tim Geyssens, Casey Neehouse and Petr Snobelt and the rest of the Umbraco world for such an awesome application and community. For all of the grief that Umbraco is given about documentation being sparse and decentralized - after you spend a couple of weeks in the forums, setting up your Umbraco tag at del.icio.us and technorati, and learning XSLT, those concerns evaporate and you begin to see an unrivaled depth of support, content and community.