Support merged resource dictionaries
Merged resource dictionaries (https://msdn.microsoft.com/en-us/library/vstudio/aa350178(v=vs.100).aspx) allow for splitting up XAML resources across multiple files and reuse of XAML resources in a more granular way than app-wide resources. They are a powerful tool in XAML application programming that is missing in Xamarin.Forms.
This is available since Xamarin.Forms 2.5.0.
Mathieu Fillion commented
Without this, we're forced to maintain a 2000+ line app.xaml. Xamarin forms is based on the xaml language, it needs include merged dictionaries. (real ones, not the very limited "MergeWith" property.
Chris Tartamella commented
I would say this is a requirement to get any usage in enterprise environments. I need someway of sharing templates and styles across assemblies and this is really the only way to do it.
i'm waiting for.....this
Without MergedDictionaries, Xamarin Forms is not usable for big companies/projects. Keep in mind that the mobile platform is - at least for some companies - not the only client. It is usually an extension of an existing environment. In my concrete case we have hundreds of xaml files containing custom styles and themes for our inhouse application. If there is no way we can share these styles with the mobile platform (share != copy) the business case with Xamarin becomes much worse (=more effort to adapt and/or rewrite).
Chase Florell commented
I'm all outta votes, but I +3 this in combination with https://xamarin.uservoice.com/forums/144858-xamarin-product-suggestions/suggestions/9993753-unseal-resourcedictionary-so-we-can-create-our-own