EF core 2.0无法运行Scaffold-DbContext

Question

我正在练习＆＃34; https://docs.microsoft.com/en-us/ef/core/get-started/aspnetcore/existing-db＆＃34;，创建了asp.net web核心应用程序，创建了数据库，并安装了三个软件包，但是当我运行时它出错了＆＃34;支架-的DbContext ...＆＃34;

＆＃13;

＆＃13;

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.5" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="2.0.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="2.0.1" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.0.2" />
  </ItemGroup>

  <ItemGroup>
    <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.2" />
  </ItemGroup>

</Project>

＆＃13;

＆＃13;

＆＃13;

重启vs2017，还是错！

我的环境：VS2017 15.5

PMC版本：4.5.0.4685

Blogging.Web.csproj

＆＃13;

＆＃13;

public static async clickIfDisplayed(targetElement: ElementFinder) {
    const isPresent = await targetElement.isPresent();
    if (isPresent) {
        const isDisplayed = await targetElement.isDisplayed();
        if (isDisplayed) {
            await PageHelper.click(targetElement);
        }
    }
}

＆＃13;

＆＃13;

＆＃13;