构建针对完整 .NET Framework 4.6.2 的默认 .NET Core 控制台应用程序时出错

Question

我一直在尝试使用 .NET Core CLI 工具学习 .NET Core 编程的基础知识。我下载了 Windows 版本 1.0.1 的 .NET Core SDK，并按照下载页面 (https://www.microsoft.com/net/core#windows) 上的简单说明进行操作：

mkdir hwapp
cd hwapp
dotnet new
dotnet restore
dotnet run

这可以在我的 Windows 10 x64 机器上编译并且 运行 没问题。

当我尝试在同一个应用程序中以 .NET Framework 4.6.2 为目标时，我 运行 遇到了麻烦。根据我的阅读，我只需要在 "frameworks" 节点下添加一个值为 "net462" 的节点：

{
  "net462": {}
}

然而，在添加此节点后，运行使用 dotnet restore 和 dotnet build CLI 命令，我收到以下错误：

Project hwapp (.NETFramework,Version=v4.6.2) will be compiled because expected outputs are missing
Compiling hwapp for .NETFramework,Version=v4.6.2
C:\Program Files\dotnet\dotnet.exe compile-csc @C:\Development\dotNet\hwapp\obj\Debug\net462\dotnet-compile.rsp returned Exit Code 1
C:\Development\dotNet\hwapp\obj\Debug\net462\dotnet-compile.assemblyinfo.cs(2,11): error CS0246: The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)
C:\Development\dotNet\hwapp\obj\Debug\net462\dotnet-compile.assemblyinfo.cs(3,11): error CS0246: The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)
C:\Development\dotNet\hwapp\obj\Debug\net462\dotnet-compile.assemblyinfo.cs(4,11): error CS0246: The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)
C:\Development\dotNet\hwapp\obj\Debug\net462\dotnet-compile.assemblyinfo.cs(5,11): error CS0246: The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)
C:\Development\dotNet\hwapp\obj\Debug\net462\dotnet-compile.assemblyinfo.cs(2,58): error CS0518: Predefined type 'System.String' is not defined or imported
C:\Development\dotNet\hwapp\obj\Debug\net462\dotnet-compile.assemblyinfo.cs(3,54): error CS0518: Predefined type 'System.String' is not defined or imported
C:\Development\dotNet\hwapp\obj\Debug\net462\dotnet-compile.assemblyinfo.cs(4,67): error CS0518: Predefined type 'System.String' is not defined or imported
C:\Development\dotNet\hwapp\obj\Debug\net462\dotnet-compile.assemblyinfo.cs(5,62): error CS0518: Predefined type 'System.String' is not defined or imported
C:\Development\dotNet\hwapp\Program.cs(1,7): error CS0246: The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)
C:\Development\dotNet\hwapp\Program.cs(5,18): error CS0518: Predefined type 'System.Object' is not defined or imported
C:\Development\dotNet\hwapp\Program.cs(7,33): error CS0518: Predefined type 'System.String' is not defined or imported
C:\Development\dotNet\hwapp\Program.cs(7,23): error CS0518: Predefined type 'System.Void' is not defined or imported

Compilation failed.
    0 Warning(s)
    12 Error(s)

从输出中可以看出，当以 .NET Framework 4.6.2 为目标时，编译器似乎无法找到系统命名空间。当我尝试定位早期的 .NET Frameworks（如 4.6.1 和 4.5.2）时出现同样的错误。

我尝试将 System.dll 和 mscorlib.dll 的 x64 版本的副本从 GAC 移动到 C:\Program Files\dotnet\ 目录，以便 csc.exe 程序可以找到系统命名空间但没有成功。

如果有帮助，请在下面找到我的 project.json 文件的内容：

{
  "version": "1.0.0-*",
  "buildOptions": {
    "debugType": "portable",
    "emitEntryPoint": true
  },
  "dependencies": {},
  "frameworks": {
    "net462": {},
    "netcoreapp1.0": {
      "dependencies": {
        "Microsoft.NETCore.App": {
          "type": "platform",
          "version": "1.0.1"
        }
      },
      "imports": "dnxcore50"
    }
  }
}

如有任何帮助，我们将不胜感激！

Answer 1

如果您想要以 .Net 4.6.2 为目标，您需要安装 .NET Framework 4.6.2 Developer Pack。