How to implement Inherited interfaces in C#

Question

I am not sure what this is called so I most likely calling it wrong when I say Inherited interface. Here is what I am trying to achieve.

I have an interface like this

 public interface INotificationEngine
    {
        bool UsingDbMail();

        bool UsingSMTP();

        bool UsingSMS();
    }

My class looks like this

 public class NotificationEngine
    {
        public class Send : INotificationEngine
        {
            public bool UsingDbMail(string para)
            {
                throw new NotImplementedException();
            }

            public bool UsingSMTP()
            {
                throw new NotImplementedException();
            }

            public bool UsingSMS()
            {
                throw new NotImplementedException();
            }
        }
    }

That allows me to do something like the following

NotificationEngine.Send sendRequest = new NotificationEngine.Send();
sendRequest.UsingDbMail("hello");

What I want to achieve instead is the following

NotificationEngine engine = new NotificationEngine();
engine.UsingDbMail("hello").Send;

Any idea how can I do that with interfaces or any other way?

UsingDbMail() is returning a bool, and a boolean value does not have the property Send. Please edit your question to include a detailed description of what you are trying to do. — Progman
– Progman, Commented Dec 29, 2021 at 2:19
Presumably you meant you want engine.UsingDbMail("hello").Send(); (a method named Send on an object returned by the UsingSomething methods); have an interface with the Send member exposed, and have your UsingXyz methods return an object that implements this interface. — Mathieu Guindon
– Mathieu Guindon, Commented Dec 29, 2021 at 2:22
Like, public IMailerService UsingDbMail(string body), and then have a class DbMailerService : IMailerService and then you'll have a SmtpMailerService : IMailerService, and so on. — Mathieu Guindon
– Mathieu Guindon, Commented Dec 29, 2021 at 2:23
@MathieuGuindon you are a super genius :) thank you so much, that does it. Not sure why I did not think of that - Post as answer please so I can mark it as answered. — Ali
– Ali, Commented Dec 29, 2021 at 2:27

Mathieu Guindon · Accepted Answer · 2021-12-29 02:37:30Z

1

Start with your common interface, it probably needs to look something like this:

interface IMailerService
{
    bool Send ():
}

You'll want an implementation that uses dbmail, another for SMTP, and another for SMS. Construct an instance of these classes in each of your "UsingXyz" methods (note: no need for a nested class here):

public IMailerService UsingDbMail(...)
{
    return new DbMailerService(...);
}

public IMailerService UsingSmtp(...)
{
    return new SmtpMailerService(...);
}

public IMailerService UsingSms(...)
{
    return new SmsMailerService(...)
}

Now when you call a UsingXyz method, you get an object that exposes a Send method that it implements as needed:

engine.UsingSms(...).Send(); // sends a SMS message

answered Dec 29, 2021 at 2:37

Mathieu Guindon

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1 Comment

Ali Over a year ago

That's brilliant, thanks so much

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