EF 7 ASP.NET 4.51,"No database providers are configured."

EF 7 with ASP.NET 4.51, "No database providers are configured."

尝试在 Web api 2 (asp.net 4.51) 应用程序中使用 EF7 上下文时出现此错误。

No database providers are configured. Configure a database provider by overriding OnConfiguring in your DbContext class or in the AddDbContext method when setting up services.

我使用的是传统 web.config

<connectionStrings>
    <add name="MemberContext" connectionString="...." 
         providerName="System.Data.SqlClient">
</connectionStrings>

我正在使用 ninject 注入上下文实例。

你需要这样的东西:

public class YourDbContext : DbContext
{

    ...

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("DefaultConnection");
        base.OnConfiguring(optionsBuilder);
    }
}