Add documentation for the creation of cross-targeted libraries

[jeromelaban]

The creation of cross-targeted libraries is not documented, and there are a few known issues around its use:

• Add references may fail
• There is no detection of the installed UWP SDK, and the version used by the project must match an installed version
• Conditionals are not handled properly by the UI
• There is no UI for adding references to assemblies that are not part of the default set of xamarin assemblies .
• Document how to use the Add Item menu in VS
• UWP head min version must match the library's target framework version.

[davidjohnoliver]

see also #3923 ;)

[ramtinak]

Can you please share a open source library that made it via uno?

[jeromelaban]

@ramtinak what are you looking for as an example for library ? Any particular feature or configuration ?

[ramtinak]

@jeromelaban anything! I just want to learn how it works. And how can I do it.

[jeromelaban]

Here's a basic control library: https://github.com/unoplatform/Uno.Samples/tree/master/UI/ControlLibrary

GitHub

unoplatform/Uno.Samples

A collection of code samples for the Uno Platform. Contribute to unoplatform/Uno.Samples development by creating an account on GitHub.