How to register multiple implementations of the same interface in Asp.Net Core?

Question

I have services that are derived from the same interface.

public interface IService { }
public class ServiceA : IService { }
public class ServiceB : IService         


        

Answer 1

Why not use inheritance? This way we can have as many copies of the interface as we want and we can pick suitable names for each of them . And we have a benefit of type safety

public interface IReportGenerator
public interface IExcelReportGenerator : IReportGenerator
public interface IPdfReportGenerator : IReportGenerator

Concrete classes:

public class ExcelReportGenerator : IExcelReportGenerator
public class PdfReportGenerator : IPdfReportGenerator

Register:

instead of

services.AddScoped();
services.AddScoped();

we have :

services.AddScoped();
services.AddScoped();

Client:

public class ReportManager : IReportManager
{
    private readonly IExcelReportGenerator excelReportGenerator;
    private readonly IPdfReportGenerator pdfReportGenerator;

    public ReportManager(IExcelReportGenerator excelReportGenerator, 
                         IPdfReportGenerator pdfReportGenerator)
    {
        this.excelReportGenerator = excelReportGenerator;
        this.pdfReportGenerator = pdfReportGenerator;
    }

this approach also allows for louse coupled code, because we can move IReportGenerator to the core of the application and have child interfaces that will be declared at higher levels.