EF Core Migration error: “Unable to create an object of type 'ApplicationContext'”

问题

I'm trying to do the migration with EF Core but I get an error - how can I fix this error?

PM> add-migration ini

Unable to create an object of type 'ApplicationContext'. Add an implementation of 'IDesignTimeDbContextFactory' to the project, or see https://go.microsoft.com/fwlink/?linkid=851728 for additional patterns supported at design time.

回答1:

This will also happen if you have multiple start-up projects - when migrating, just select one (in VS right click Solution and Set StartUp Projects...)

回答2:

1.Modify your code in ConfigureService with :

options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"),

        x => x.MigrationsAssembly("WebApplication")));

2. In command line which includes WebApplication.csproj:

dotnet ef migrations add Init

来源：https://stackoverflow.com/questions/51343295/ef-core-migration-error-unable-to-create-an-object-of-type-applicationcontext