我发现，当我们在 project.json 中的 dependencies 下缺少以下内容时，就会发生这种情况>

I figured it out that this happens when we are missing the following under the dependencies in project.json

"Microsoft.NETCore.App": {
      "version": "1.0.1",
      "type": "platform"
    }

注意(如果上述版本错误)，我们也会看到相同的错误.

NOTE If the version is wrong (in the above mentioned) then also we see the same error.