Entity framework .Net核心，使用实体框架搭建时出错

我试图创建一个利用实体框架脚手架选项的控制器，但它根本不起作用，错误如下：

.csproj在这里：

 <ItemGroup>
    <PackageReference Include="AutoMapper" Version="6.1.1" />
    <PackageReference Include="AutoMapper.Extensions.Microsoft.DependencyInjection" Version="2.0.1" />
    <PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.0.0" />
    <PackageReference Include="Microsoft.AspNetCore" Version="1.1.2" />
    <PackageReference Include="Microsoft.AspNetCore.Mvc" Version="1.1.3" />
    <PackageReference Include="Microsoft.AspNetCore.StaticFiles" Version="1.1.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="1.1.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="1.1.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer.Design" Version="1.1.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="1.1.1" />
    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="1.1.2" />
    <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="1.1.2" />
    <PackageReference Include="Microsoft.VisualStudio.Web.BrowserLink" Version="1.1.2" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="1.1.1" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGenerators.Mvc" Version="1.1.1" />
  </ItemGroup>
  <ItemGroup>
    <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="1.0.1" />
    <DotNetCliToolReference Include="Microsoft.Extensions.SecretManager.Tools" Version="1.0.1" />
    <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="1.0.1" />
  </ItemGroup>

我的DbContext将DbSet与我试图在脚手架中使用的模型连接起来：

public DbSet<Tarefa> Tarefas { get; set; }

公共DbSet Tarefas{get；set；} 我不仅尝试了模型，还尝试了ViewModel，但结果是一样的。

---

有人能告诉我我缺少什么吗？

你能分享一下

DbContext

和

Tarefa

模型类吗？嘿@Sanket，这里是：DbContext:Tarefa类：你能分享

DbContext

和

Tarefa

模型类吗？嘿@Sanket，这里是：DbContext:Tarefa类：