Extension methods for more concise registration of IConfigureOptions/IPostConfigureOptions

[tuespetre]

services.AddSingleton<IConfigureOptions<MvcOptions>, MyConfigureMvcOptions>() seems unwieldy and non-obvious. I believe a friendlier, more discoverable alternative would be services.Configure<MvcOptions, MyConfigureMvcOptions>().

public static IServiceCollection Configure<TOptions, TConfigureOptions>(this IServiceCollection services)
    where TOptions : class
    where TConfigureOptions : class, IConfigureOptions<TOptions>
{
    return services.AddSingleton<IConfigureOptions<TOptions>, TConfigureOptions>();
}

public static IServiceCollection Configure<TOptions, TPostConfigureOptions>(this IServiceCollection services)
    where TOptions : class
    where TPostConfigureOptions: class, IPostConfigureOptions<TOptions>
{
    return services.AddSingleton<IPostConfigureOptions<TOptions>, TPostConfigureOptions>();
}

[HaoK]

We used to have sugar for this early in 1.0 which we removed near 1.0 RTM, we actually allowed registration of a global setup class, and would reflect on it registering all IConfigureOptions it implemented.

i.e.

  services.RegisterOptionsSetup<MyConfigure>(); // Reflects and registers all of the appropriate

  class MyConfigure : IConfigureOptions<MvcOptions>, IConfigureOptions<RazorOptions>, IPostConfigureOptions<MvcOptions> {
     // implement everything you want in one class
  }

We could bring something similar back