.Net Core service is not getting registered

Question

I have the following two classes with interface

public interface IInterface1
{
 //declarations
}

public class class1 : IInterface1
{
 //definitions
}

public interface IInterface2
{
//declarations
}

public class class2 : IInterface2
{
   private readonly IInterface1 _interface;
   //constructor
   public class2(IInterface1 interface1)
   {
     //getting null for interface1
     _interface = interface1;
   }
}

and a controller where i'm injecting the IInterface2

public class MyController : Controller
{
  private readonly IInterface2 _usecase;
  public MyController(IInterface2 usecase)
  {
    _usecase = usecase;
  }
}

and in Startup.cs i have registered service like this

public void ConfigureServices(IServiceCollection services)
{
  services.AddScoped<IInterface2, class2>();
  services.AddScoped<IInterface1, class1>(x => (class1)x.GetService<IInterface1>());
}

the issue which facing is when i'm injecting the IInterface1 in class2 not able to access the properties of the interface1 in constructor instead getting null

Answer 1

The example you showed in the question works well if you replace the configuration with this :

public void ConfigureServices(IServiceCollection services)
{
  services.AddScoped<IInterface2, class2>();
  services.AddScoped<IInterface1, class1>();
}

Note that the line you wrote :

services.AddScoped<IInterface1, class1>(x => (class1)x.GetService<IInterface1>())

is causing Access Violation

(Because, when Interface1 is needed, dependency system will try to get ... an Interface1 from the dependency system using GetService , executing this rule in an infinite recursion)

We need more details to understand your problem and help solving it.

You may need to create a factory for your classes, or solve the circular dependency you mentionned in comments, that apparently prevents you from using the simple injection shown here.