Cannot reference .NET Core library from UWP

Question

I have a .NET Core library with the following project.json:

{
  "version": "1.0.0-*",
  "dependencies": {
    "NETStandard.Library": "1.6.0"
  },
  "frameworks": {
    "netstandard1.6": { }
  },
  "scripts": {
    "postcompile": [
      "dotnet pack --no-build --configuration Release",
      "xcopy bin\\Release ..\\..\\lib\\ /Y"
    ]
  }
}

where the postcompile script creates a nuget package which I added as a custom feed in VS, following these instructions. This is because I want to reference it from a Windows Universal App, which cannot be otherwise (yet), according to this question. But when I try it, I get this message:

Package AEther 1.0.0 is not compatible with uap10.0 (UAP,Version=v10.0).
Package AEther 1.0.0 supports: netstandard1.6 (.NETStandard,Version=v1.6)
One or more packages are incompatible with UAP,Version=v10.0.

This is where it stops making sense to me. According to this, it should work fine for netstandard >=1.6.0, while this official table says I need to target netstandard <=1.4.0, but that doesn't change anything. More confusingly, if I downgrade both versions of netstandard (the dependency and the target framework) to, say, 1.5, I still get this exact same error without specifying 1.6 in any of my files.

Update The UWP project.json looks like this

{
  "dependencies": {
    "Microsoft.NETCore.UniversalWindowsPlatform": "5.2.1"
  },
  "frameworks": {
    "uap10.0": {}
  },
  "runtimes": {
    "win10-arm": {},
    "win10-arm-aot": {},
    "win10-x86": {},
    "win10-x86-aot": {},
    "win10-x64": {},
    "win10-x64-aot": {}
  }
}

Can someone clear up either

1. How to reference .Net Core libraries from UWP at all or
2. What is going on in my specific case?

ANSWER

I solved it adding an import to the UWP app as follows:

{
  "dependencies": {
    "Microsoft.NETCore.UniversalWindowsPlatform": "5.2.1"
  },
  "frameworks": {
    "uap10.0": { import [ "netstandard1.6" ] }
  },
  "runtimes": {
    "win10-arm": {},
    "win10-arm-aot": {},
    "win10-x86": {},
    "win10-x86-aot": {},
    "win10-x64": {},
    "win10-x64-aot": {}
  }
}

Answer 1

您需要将Microsoft.NETCore.UniversalWindowsPlatform升级到5.2.1

7月15日更新

好的，这是我的结果

1. 创建新的UWP
2. 升级到5月14日发布的5.2.2

3. 更新project.json，import＆＃34; netstandard1.6＆＃34;

   { "dependencies": { "Microsoft.NETCore.UniversalWindowsPlatform": "5.2.2", "Test": "1.0.0" }, "frameworks": { "uap10.0": { "imports": [ "netstandard1.6" ] } }, "runtimes": { "win10-arm": {}, "win10-arm-aot": {}, "win10-x86": {}, "win10-x86-aot": {}, "win10-x64": {}, "win10-x64-aot": {} } }

4. 创建一个新的dotnet核心库

5. 构建库，并生成nuget包
6. 我可以引用.dll文件或nuget包。而 在输入代码时变得聪明
7. UWP已成功构建和部署，但一旦运行它，就会抛出异常

Answer 2

  

这是我不再理解的地方。根据这个，它   应该适用于netstandard＆gt; = 1.6.0，而这个官方表   说我需要针对netstandard＆lt; = 1.4.0，但这并没有改变   任何东西。更令人困惑的是，如果我降级两个版本的   netstandard（依赖和目标框架），比方说，1.5，I   仍然得到这个完全相同的错误，而没有在我的任何一个指定1.6   文件。

Universal Windows Platform maps to netstandard1.4 - 既不是1.6也不是1.5。因此，您的库（我认为称为AEther）的要求比您的UWP应用程序要高。

  

  
1. 如何从UWP中引用.Net核心库或
  

如your linked SO question中所述，Visual Studio中尚不支持此功能。

我只能猜测它与CLI的支持有关，即an open issue。截至今天，预计将在Microsoft.NETCore.UniversalWindowsPlatform元数据包的5.3版中修复 - 尽管之前预计会在5.2.2中修复。

  

  
1. 我的具体情况是怎么回事？
  

NuGet告诉您，您的软件包仅支持netstandard1.6 target framework，但不支持uap10.0。实际上，如果您打开.nupkg的密码，就会在lib\netstandard1.6下找到您的DLL。

由于dotnet pack会自动从.nuspec创建project.json，因此您需要使用适当的框架（例如netstandard1.4）进行修复。对于不同的框架，它可能更容易编译，例如Portable profiles compatible with .NET Platform Standard。