Your startup project doesn't reference Microsoft.EntityFrameworkCore.Design

Question

I have 2 projects in my solution, I have a project with Entity Framework Core installed:

And in the other ASP.NET Web API project I have these packages:

Answer 1

Set the project with entities as the Startup project and run the scaffolding command. it worked for me. Don't forget to set the revert the startup project after.

Answer 2

I got this error because Visual Studio defaulted to using entity framework core rather than old-school entityframework for .NET Framework: entity framework 6. This was my solution:

EntityFramework\Update-Database

Or reference the version explicitly:

EntityFramework6\Update-Database

Also worth checking the right project is selected in the Package Manager Console. That likes to sneak back to other projects half the time!

Answer 3

There is absolutely NO reason to install Microsoft.EntityFrameworkCore.Design to your API project while having a separate Data project.

Quick solution

When using add-migration, just add a parameter to set the -StartUpProject to your Data proj (by default I presume your startup project is the API proj).

---

Example add-migration command below:

add-migration {migration_name} -StartUpProject {your_data_proj_name} -project {your_data_proj_name} -v

---

Example update-database command below:

add-migration {migration_name} -StartUpProject {your_data_proj_name} -project {your_data_proj_name} -v

---

I hope this help you guys

PS: more info about the add-migration params can be found here

Answer 4

I found the solution here: http://obscureproblemsandgotchas.com/development/c/dotnet-core-ef-migration-not-working/

In short, edit your csproj file, and add to your PropertyGroup section following entry:

<GenerateRuntimeConfigurationFiles>True</GenerateRuntimeConfigurationFiles>

Answer 5

Try to set your web project again as startup project and this warning should go. (Right click on web project > Set as startUp project)

Answer 6

In order for the migration tool to work, I had to add the Microsoft.VisualStudio.Web.CodeGeneration.Design NuGet package as well.