命名空间“Microsoft”中不存在“EntityFrameworkCore”

Question

I follow this tutorial: https://docs.microsoft.com/en-us/ef/core/get-started/full-dotnet/new-db step by step

but I cannot add the "Microsoft.EntityFrameworkCore " namespace to Model.cs

I use Visual studio 2017

and install Microsoft.EntityFrameworkCore.SqlServer(1.1.2) ,

Microsoft.EntityFrameworkCore.Tools (1.1.1) ,

and .NET Framework 4.5.2

Visual Studio says:

The type or namespace name 'EntityFrameworkCore' does not exist in the namespace 'Microsoft' (are you missing an assembly reference?)

They added to .csproj :

Answer 1

Copying the following code into the TodoApi.csproj from https://github.com/aspnet/Docs/tree/master/aspnetcore/tutorials/first-web-api/sample/TodoApi worked for me on a similar issue.

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

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

  <ItemGroup>
    <Folder Include="wwwroot\" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />
  </ItemGroup>

  <ItemGroup>
    <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.0" />
  </ItemGroup>

</Project>

Microsoft.AspNetCore.All may be excessive but it includes EntityFrameworkCore etc

Answer 2

C:\Program Files\dotnet\sdk\6.0.300\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.DefaultItems.Shared.targets(90,5): Error: The Microsoft.AspNetCore.All package is not supported when targeting .NET Core 3.0 or higher. A FrameworkReference to Microsoft.AspNetCore.App should be used instead, and will be implicitly included by Microsoft.NET.Sdk.Web.

For anyone at 3.0 or higher with same error