相关疑难解决方法(0)

我在NET Core2.0 App中有以下类.

// required when local database does not exist or was deleted
public class ToDoContextFactory : IDesignTimeDbContextFactory<AppContext>
{
    public AppContext CreateDbContext(string[] args)
    {
        var builder = new DbContextOptionsBuilder<AppContext>();
        builder.UseSqlServer("Server=localhost;Database=DbName;Trusted_Connection=True;MultipleActiveResultSets=true");
        return new AppContext(builder.Options);
    }
}

当Database不存在时,在Core 2.0中需要进行迁移,并且必须在运行update-database时创建.
升级到ASP.NET Core 2.0后无法创建迁移

我想在2个地方(这里和appsettings.json)没有ConnectionString,但只在.json,所以我试图更换

"Server=localhost;Database=DbName;Trusted_Connection=True;MultipleActiveResultSets=true"

同

ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString

但它不起作用,我得到空值.

更新1:
请注意,在Core 2中明确添加.json是不必要的,所以问题不在于文件.
https://andrewlock.net/exploring-program-and-startup-in-asp-net-core-2-preview1-2/

更新2:
此外,我已经使用Configuration从.json向Context发送ConnectionString:

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddDbContext<AppContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"))); …