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I'm trying to use DI to bind a different implementation of my networking class. I've been able to do this successfully using a none generic version of the class. My implementation is as follows:

class MainClass

 public static void Main(string[] args)
 
 IKernel kernel;

 // Hardcode here but will be managed by build system.
 bool runningInProd = false;

 if (runningInProd)
 
 kernel = new StandardKernel(new RealNetworkModule());
 
 else
 
 kernel = new StandardKernel(new FakeNetworkModule());
 

 Session session = kernel.Get<Session>();

 session.Authenticate();
 

 public class RealNetworkModule : NinjectModule
 
 public override void Load()
 
 Bind(typeof(IRequestSender)).To(typeof(RealRequestSender));
 
 

 public class FakeNetworkModule : NinjectModule
 
 public override void Load()
 
 Bind(typeof(IRequestSender)).To(typeof(FakeRequestSender));
 
 

Class that uses my IRequestSender:

public class Session

 IRequestSender requestSender;

 [Inject]
 public Session(IRequestSender requestSender)
 
 this.requestSender = requestSender;
 

 public void Authenticate()
 
 Console.WriteLine(requestSender.Send("Hello There"));
 

The IRequestSender interface:

public interface IRequestSender

 string Send(string request);

And the two different implementations:

public class RealRequestSender: IRequestSender

 public string Send(string request)
 
 return "RealRequestSender right back at you: " + request;
 


public class FakeRequestSender: IRequestSender

 public string Send(string request)
 
 return "FakeRequestSender right back at you: " + request;
 

This is very straightforward and it works; however, what I need is for my IRequestSender to use Generic types rather than string for input output:

public interface IRequestSender<RequestT, ResponseT> where RequestT: class where ResponseT: class

 RequestT Send(RequestT request);

And the impl's:

public class FakeRequestSender<RequestT, ResponseT> : IRequestSender<RequestT, ResponseT> where RequestT : class where ResponseT : class

 public RequestT Send(RequestT request)
 
 throw new NotImplementedException();
 


public class RealRequestSender<RequestT, ResponseT> : IRequestSender<RequestT, ResponseT> where RequestT : class where ResponseT : class

 public RequestT Send(RequestT request)
 
 throw new NotImplementedException();
 

I've come across several examples that address this issue and I've tried to base my implementation on them but I have failed. Here are the two problems that I'm running into:

1) Binding: this is the main problem. Here is what my binding looks like based on solutions I have seen online:

public class RealNetworkModule : NinjectModule

 public override void Load()
 
 Bind(typeof(IRequestSender<>)).To(typeof(RealRequestSender<>));
 

VSCode gives me the error:

Program.cs(29,29): Error CS0305: Using the generic type 'IRequestSender<RequestT, ResponseT>' requires 2 type arguments (CS0305) (DI)

Based on this error and what I have read online it is still not clear to me what I need to do here.

2) Accessing IRequestSender: the solution to this might be clear once I know how to fix binding. In the original implementation I used [Inject] to get access to the IRequestSender I need in my Sessions class. However now in the generic version I imagine I will not be able to do this. If I were to use RequestSender without DI it would look like:

RequestSender <AuthRequest, AuthResponse> requestSender = new RequestSender<AuthRequest, AuthResponse>();

or

RequestSender <UserRequest, UserResponse> requestSender = new RequestSender< UserRequest, UserResponse >();

for any number of different types.

So I'm not sure how to go about accessing the RequestSender in this scenario.

Given your current interface, you'll have to specify the generic type arguments when injecting. Assuming your request and response are both strings, your constructor would look like:

public Session(IRequestSender<string, string> requestSender)

 this.requestSender = requestSender;

If you don't want to specify the arguments at creation/injection time, you'll have to change the design a bit. I can't say for certain with the sample code you provided, but it might be possible to remove the generic type args from your interface and place them on the method instead:

public interface IRequestSender

 RequestT Send<RequestT, ResponseT>(RequestT request)
 where RequestT: class
 where ResponseT: class;

With that definition, you'd inject IRequestSender, and then specify the generic type parameters when calling. For example,

string myResponse = requestSender.Send<string, string>("my string");