Cross Project MergedDictionaries in Silverlight

Todd Miranda has posted a video on the use of merged dictionaries on the Learning portal of Silverlight.net (find it here). This video explains the concepts of MergedDictionaries in a very long winded way. IMHO people investigating MergedDictionaries will already know how to layout a grid, and play some simple controls, so the first 8m of the tutorial is pretty boring.

The description of the use of MergedDictionaries is pretty good, along with a couple of common pitfalls, but this does not explain one core feature well enough: Cross Project

Anyone writing a Silverlight LOB application is almost certainly going to have multiple projects, and the use of MergedDictionaries corss project is going to be a huge advantage.

Luckily this isn’t much more difficult than Todd has shown. Imagine the following scenario; we have a bunch of silverlight pages that need to share styles, but are spread across a few different projects. We want to keep the styles (as resources) in one location and reference these.

So simply create a Resources project, and add your resources files as described by Todd (Add | New Item… | XML file etc) (you can also add these to any sensible location in your existing solution – say a UserControls project)

Then when referencing the MergedDictionary from the UserControl where the style will be applied, use the Assembly name of the resources location, rather than the assembly name of the UserControl location.

So the Source value will be formatted as Source=”/[AssemblyName];component/[Path and filename]“

Don’t forget to add a reference to the Resources project from the Target Project.

Further details and and example of this in action with a re-styled TransitioningContentControl can be found here: http://thoughtjelly.blogspot.com/2009/10/restyling-transitions-in-silverlight.html.