Authoring/Hosting project tooling support

[angelazhangmsft]

Creating an issue to track the status of end-to-end C# Authoring/Hosting. Here is a list of hacks that we should remove to consider authoring/hosting experience complete:

• Instead of winmd reference from hosting project, allow for project reference to the component - Joshua
• Remove need for DeploymentContent set to true in hosting project file (for the manifest and runtimeconfig) - Joshua
• Automate activatable classes instead of manually creating manifest file - Mano (Automate activatable classes instead of manually creating manifest file #789)
• Remove need for creating WinRT.Host.runtimeconfig.json (create a default, and allow override) - Joshua ([Authoring] Support for a default WinRT.Host.runtimeconfig  #735)
• CsWinRTEnableLogging in authoring csproj (Warning when turning of CsWinRTEnableLogging #687) - Mano
• CsWinRTWindowsMetadata (Reduce need for CsWinRTWindowsMetadata #657)
• GeneratedFilesDir in authoring csproj bug with potential race condition - Mano
• AssemblyVersion - can we set a default
• Copy hosting dlls so you don't need Directory.build.targets files (Add WinRT.Host to nuget package for C# authoring #474)

For packaged apps, there are some additional hacks:

• Manually copying CsWinRT and component assemblies to the Appx folder on deploy ([Authoring] Packaged apps do not get necessary dlls in Appx folder #734)
• Manually editing the appxmanifest (may need VS help), for example:

<Extensions>
    <Extension Category="windows.activatableClass.inProcessServer">
      <InProcessServer>
        <Path>WinRT.Host.dll</Path>
          <ActivatableClass ActivatableClassId="Net5BgTaskComponent.BgTask" ThreadingModel="both" />
      </InProcessServer>
    </Extension>
  </Extensions>

Other existing issues for E2E authoring support include:

• Hosting support loading same binary in multiple assembly loader context causing type cast issues #633
• Dependent WinMDs of authored component should be automatically detected #656
• [Diagnostics] Check against WindowsRuntimeType attribute when checking types #649
• Authoring with user control - diagnostics catching Xaml generated file #662

[j0shuams]

Hosting support needs some more work with ProjectReferences, but PackageRef's are handled by my PR #665

[j0shuams]

Meeting notes:

Top priority is project reference support, as a few of the later hacks we want to see if they are needed once projref support is in place.

Second priority: manifest/runtimeconfig

• Mano will work on embedding manifest in authored component, with the hope that consumers wont need to make a manifest file at all.

• Joshua will work on making a generic runtimeconfig, and shipping it with DeploymentContent metadata -- consumers wont need to author one unless they want to make a custom one (by referring to the hosting docs)

Re: docs page, Angela will help me by setting up a webpage based on the old one I linked in #677

[angelazhangmsft]

Closing and tracking the remaining items separately