How do I reference a Class Library (WinUI 3 Desktop) in Solution_AAA from Solution_BBB?

Kenny Brown 51

I generated a C# projection from a C++/WinRT component to distribute as a NuGet package for .NET 5+ applications and need to use it in a WinUI 3 Desktop App that is in it's own solution.

Solution_AAA contains:
DirectWriteCore is a C++ Windows Component (WinUI 3)
DirectWriteCore_API is a C# Class Library (WinUI 3 in Desktop)

Solution_BBB contains:

??? The project (C# WinUI 3 in Desktop) that needs access to DirectWriteCore_API (to access DirectWriteCore, which accesses DWriteCore in WindowsAppSDK) ???

Thank you, in advance, for any assistance.

Jack J Jun 24,296 Reputation points Microsoft Vendor

2021-10-04T01:54:49.537+00:00

@KennyBrown-6273, Since your problem is related to WinUI 3, I suggest that you could ask the question in GitHub.
Kenny Brown 51 Reputation points

2021-10-04T02:10:34.033+00:00

"learn.microsoft.com" - Microsoft built and is distributing WinUI 3 in the form of Windows App SDK, or soon will be (.NET5, .NET6, Windows 11, etc.). I do realize some things are still in experimental stage, so that is why I'm using the Windows App SDK Experimental release instead of Preview release in my builds. The information I have gathered, that has been most useful, has come from learn.microsoft.com. And, yes - I understand Microsoft owns GitHub and is another place to look for answers, and have. Thus, good suggestion, to use as many resources as possible to find answers. This is my attempt at using this resource.
Kenny Brown 51 Reputation points

2021-10-04T14:57:05.24+00:00

I have added, as projects, DirectWriteCore and DirectWriteCore_API (as an existing item, referenced them by drilling back-then-down to their respective project file). I then added:
<PackageReference Include="DirectWriteCore" Version="0.1.0-prerelease" /> to the WinUI 3 app's .csproj file.

I can see DirectWriteCore in NuGet Package Manager and is installed for the project in question. I can see it as one of the Packages in Dependencies. But, neither #using DirectWriteCore or #using DirectWriteCore_API work, I get the following:

Error CS0246 The type or namespace name 'DirectWriteCore' could not be found (are you missing a using directive or an assembly reference?) Character Map C:\Source\Code\Windows\10\WinUI 3\Fonts\Character Map\Character Map\MainWindow.xaml.cs

Also added DirectWriteCore_API's project as a reference, no luck - #using did not work.

So, I referenced DirectWriteCore's project (#using worked) but get the following :

Error NETSDK1130 DirectWriteCore.winmd cannot be referenced. Referencing a Windows Metadata component directly when targeting .NET 5 or higher is not supported. For more information, see https://aka.ms/netsdk1130 Character Map C:\Program Files\dotnet\sdk\6.0.100-rc.1.21463.6\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.targets

Reference: https://learn.microsoft.com/en-us/windows/uwp/csharp-winrt/net-projection-from-cppwinrt-component

What to TRY NEXT ???
Kenny Brown 51 Reputation points

2021-10-04T16:53:08.507+00:00

Forgot to mention, I had to add the following to the .csproj so Visual Studio 2022 Preview could locate the "DirectWriteCore.0.1.0-prerelease.nupkg" file:

<PropertyGroup>
<RestoreSources>
https://api.nuget.org/v3/index.json;
../../../DirectWriteCore_API/nuget
</RestoreSources>
</PropertyGroup>
Kenny Brown 51 Reputation points

2021-10-04T17:15:55.82+00:00

Is projection the proper technique?

If so, why don't my 'using' statements work?
Kenny Brown 51 Reputation points

2021-10-05T03:31:42.15+00:00

What seems strange to me, is that Visual Studio 2022 Preview has C++ Windows Component (WinUI 3) as a template. But if "Referencing a Windows Metadata component directly when targeting .NET 5 or higher is not supported.", then what's the use of the component, if it can't be used in managed code? Currently, I have a NuGet package that is a "C++ Windows Component (WinUI 3)". How do I set up the Visual Studio environment and my source files to consume this component? What is the proper way to use 'projection', in order to have a class library?
Kenny Brown 51 Reputation points

2021-10-05T03:48:42.897+00:00

WHAT IS THE PROPER WAY TO CODE A "CLASS LIBRARY", IN VISUAL STUDIO 2022 PREVIEW (or 2019), THAT NEEDS TO USE C++ (to access DWriteCore) FROM MANAGED CODE (C#) ?