从 .Net Core 2.2 迁移到 .Net Core 3.0

Question

Hi I am trying to Migrate Web API from.Net core 2.2 to .net core 3.0 I am getting warning for the below lines code. Could you please let me know how to fix this.

 public void ConfigureServices(IServiceCollection services)

  {  
 var buildServiceProvider = services.BuildServiceProvider();
            var getService = buildServiceProvider.GetService<IOptions<ConfigurationSettings>>();
            ConfigurationSettings = getService.Value;

}

Warning:Calling BuildServiceProvider from application code results in additional copy of singleton services being created.

Thank you

Answer 1

It is because you are creating ServiceProvider. Ideally, you should not call services.BuildServiceProvider(). it looks like you are calling BuildServiceProvider so that you can resolve IOptions<ConfigurationSettings> . instead of resolving in the ConfigureServices method you can accept IOptions<ConfigurationSettings> as an argument of the service and ASP.NET Core will inject it into your service.

public class MyService : IMyService
{
    public MyService(IOtherService otherService, IOptions<ConfigurationSettings> configurationSettings)
    {
         // read config value from here.
    }
}