asp.net core 2.0 - Value cannot be null. Parameter name: connectionString

Question

I had the following error in package manager console when Add-Migration

Value cannot be null. Parameter name: connectionString

Answer 1

This worked flawlessly for me:

public IConfiguration Configuration;
public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext(options => 
            //options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
            options.UseSqlServer("Server=serverAddress; Database=dbName; user=username; password=pswd"));
}

The commented part is just as reference where to replace.