Make an object available from dependency injection via more than one type

I have the following interface and classes.

public interface IWorkingPath
{
    string WorkingFolder { get; }
}

public class WorkingPath : IWorkingPath
{
    public required string WorkingFolder { get; set; }
}

public class AppSettings : WorkingPath
{
    public bool IsStaging { get; set; }
    public bool IsStagingTrackAndTrace { get; set; }
}

And then I have the following section in my appsettings.json.

"AppSettings": {
  "IsStaging": true,
  "IsStagingTrackAndTrace": true,
  "WorkingFolder": "Xxxxx"
},

I then make these settings available to dependency injection.

AppSettings? appSettings = builder.Configuration.GetSection("AppSettings").Get<AppSettings>();
builder.Services.AddSingleton(appSettings);

This works fine, but now I have some classes that are requesting IWorkingPath from dependency injection.

Is there any way to make this same appSettings instance available for dependency injection as either AppSettings or IWorkingPath?

>Solution :

Is there any way to make this same appSettings instance available for dependency injection as either AppSettings or IWorkingPath?

Yes, just register it as such:

AppSettings appSettings = builder.Configuration.GetSection("AppSettings").Get<AppSettings>() ?? throw new InvalidOperationException( "Failed to get AppSettings instance" );

builder.Services.AddSingleton<IWorkingPath>( appSettings );
builder.Services.AddSingleton<WorkingPath >( appSettings );
builder.Services.AddSingleton<AppSettings >( appSettings );

…but a better solution would be to make the class WorkingPath implementation an internal (or move it to a scarily-named namespace) to avoid consumers requesting a class ctor parameter instead of the IWorkingPath interface.