ASP.NET Core option dependency in constructor

Question

I\'m using ASP.NET Core and I\'m attempting to create a resolvable class which has an optional parameter:

public class Foo
{
     public Foo() : this(null)
          


        

Answer 1

You need to register the IValidator first:

  var services = new Microsoft.Extensions.DependencyInjection.ServiceCollection();
  services.AddTransient, RealValidator>();
  services.AddTransient();

  var serviceProvider = services.BuildServiceProvider();
  var validator = serviceProvider.GetService>();
  var foo = serviceProvider.GetService();

  Assert.NotNull(validator);
  Assert.NotNull(foo);