Project X 以框架“.NETStandard”为目标。 实体框架 Package 管理器控制台工具不支持此框架

Question

I'm trying to create a EF 6.4 migration in my solution which has net472 projects and netstandard projects, and I'm getting the following error:

Project 'ESP.Console' targets framework '.NETStandard'. The Entity Framework Package Manager Console Tools don't support this framework.

However, the 'ESP.Console' app doesn't target .NETStandard, it's targetting net472:

  <PropertyGroup>
    <TargetFramework>net472</TargetFramework>
    <LangVersion>7.3</LangVersion>
    <OutputType>Exe</OutputType>
  </PropertyGroup>

I have ESP.Console console app set as my startup project, and I have the ESP.Data project as my default project in the Package Manager console.

This is the setup for ESP.Data.csproj :

  <PropertyGroup>
    <TargetFrameworks>netstandard2.1;net472</TargetFrameworks>
    <EmbeddedResourceUseDependentUponConvention>true</EmbeddedResourceUseDependentUponConvention>
  </PropertyGroup>

I need this to target both netstandard and net472 while I am in the process of converting other applications in the solution to run on .net core.

Why am I getting this error? Is there another command like dotnet ef I can use that will work with my EF 6.4 project?

We've used EF migrations on this solution hundreds of times, but since the last time I needed to run a migration we've done two major changes to the solution- converted all the csproj files to use the new format (with PackageReference, etc) and converted the core projects to target either .net standard 2.0 or 2.1 where needed. So I think the issue is related to that.

Attempting to change ESP.Console application to run as netcoreapp3.1 gave the same error.

Answer 1

I have found a solution to my problem, though it is a bit messy since I will need to make a temporary change to a csproj file in order to get this to run.

In my case, the ESP.Data (the project housing my DbContext ) was targeting both net472 and netstandard2.1 , I altered the Data project to remove the netstandard2.1 target framework. It seems there is a bug in VS that is saying that the StartupProject targets NetStandard instead of saying that the Target project does. After I create the migration, I can add the target back again.

I will be moving to .net core compilation soon, and will therefore need that netstandard 2.1 target at some point, so I'm not sure what I'll do when that comes. I may need to preserve a net472 console application to use in the future and continue targeting net472 in my data project after that migration is done in order to continue to create migrations.

Answer 2

I had a simular problem.
My problem was, that I was targeting netcoreapp3.1 with my startup project and used Entity Framework 6 tools .
When I switched to EntityFrameworkCore tools it worked.

Answer 3

Might be a bug in Visual Studio -- I was seeing this error after I changed the Startup Project to the correct project with my migrations, even though my project uses .NET Framework 4.8.

Tried several things with no luck, but then closing and re-opening Visual Studio fixed the problem.