Visual Studio 2017 csproj .NET CORE netstandard2.0 not building

Question

I just installed VS2017 and did the one way migration of my .NET core projects from the project.json format to the new csproj format. What I want is to target multiple frameworks so I can build a Framework Depedenent Deployment and a Self Contained Deployment using a smaller footprint. I followed the directions on the MS docs, but when I include netstandard1.6 or netstandard2.0 in the TargetFrameworks, I get a whole slew of Predefined type System.Object is not defined and The type of namespace System could not be found among others when I try and build the project. This worked when it was using the project.json file. My csproj is

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <VersionPrefix>1.0.0.0</VersionPrefix>
    <TargetFrameworks>netcoreapp1.2;netstandard2.0</TargetFrameworks>
    <AssemblyName>App</AssemblyName>
    <OutputType>Exe</OutputType>
    <PackageId>App</PackageId>
    <RuntimeFrameworkVersion Condition=" '$(TargetFramework)' == 'netcoreapp1.2' ">1.1.1</RuntimeFrameworkVersion>-->
    <NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard2.0' ">1.6.1</NetStandardImplicitPackageVersion>
    <RuntimeIdentifiers>win10-x64;android.21;android21-arm64;osx.10.12;rhel7.4;centos.7-x64;debian8-x64;ubuntu16.10-x64;fedora.26-x64;opensuse.42.1-x64</RuntimeIdentifiers>
    <GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
    <GenerateAssemblyCompanyAttribute>false</GenerateAssemblyCompanyAttribute>
    <GenerateAssemblyProductAttribute>false</GenerateAssemblyProductAttribute
  </PropertyGroup>

  <ItemGroup>
    <None Remove="App.csproj.vspscc" />
  </ItemGroup>

  <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' ">
    <PackageReference Include="System.Threading.Thread" Version="4.3.0" />
    <PackageReference Include="Microsoft.NETCore.Runtime.CoreCLR" Version="1.1.0" />
  </ItemGroup>

</Project>

My original project.json

{
  "version": "1.0.0.0",
  "buildOptions": {
    "emitEntryPoint": true
  },

  "frameworks": {
    "netcoreapp1.2": {
      "dependencies": {
        "Microsoft.NETCore.App": {
          "type": "platform",
          "version": "1.1.0"
        }
      }
    },
    "netstandard2.0": {
      "dependencies": {
        "NETStandard.Library": {
          "version": "1.6.1"
        },
        "System.Threading.Thread": "4.3.0",
        "Microsoft.NETCore.Runtime.CoreCLR": "1.1.0"
      }
    }
  },

  "runtimes": {
    "win10-x64": {}
    "ubuntu.16.10-x64": {},
    "centos.7-x64": {},
    "debian.8-x64": {},
    "fedora.24-x64": {},
    "opensuse.42.1-x64": {},
    "osx10.12-x64" : {}
  }
}

Not sure what the problem is. Am I trying to do something unsupported? If I have just netcoreapp1.2, when I do a dotnet publish -c Release -r win10-x64 I still get a FDD output, not a standalone executable. I feel like this was way easier with the json file... What am I doing wrong?

Bebben Bebben · Accepted Answer · 2017-03-17T08:19:31

I got the same error message when the Nuget-packages were not restored. Have you made sure the packages are restored properly, and that no errors appear if you run "dotnet restore"?

Visual Studio 2017 csproj .NET CORE netstandard2.0 not building

1 Answers