I have a solution with 2 projects. First is the primary application, the second has controls in it. In the Generic.xaml, in a Silverlight project, one would do
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/MyLibNamespace;component/Themes/SomeFolder/MyControl.xaml" />
</ResourceDictionary.MergedDictionaries>
This doesn’t seem to work in a Windows Store application class library. ReSharper wants the filepath to be “/Themes/SomeFolder/MyControl.xaml” but I still get a XamlParseException: Failed to assign to property ‘Windows.UI.Xaml.ResourceDictionary.Source’. [Line: 7 Position: 36]
There’s no such thing as a “Xaml file within other class/assembly” in WinRT. In other words: “EmbeddedResource” or “Resource” simply doesn’t exist in a WinRT component (and yes this is a pain). This is also why \Themes\Generic.xaml is copied out into the output directory).