You seem to be looking for a piece of code that will send emails for you. This isn’t in that book.
The code you show is in a chapter that’s titled “Building Loosely Coupled Components”:
[…] one of [the] most important features of the MVC pattern is that it enables separation of concerns. […] A simple example will help put things in context. If we were writing a component called
MyEmailSenderto send e-mail messages […]
Emphasis mine.
They’re trying to teach you the concept of building good, maintainable, testable software through separation of concerns and dependency injection.
If you’re just looking for copy-pasteable code to implement an email sending class, you’ve bought the wrong book.
If all you’re looking for is code to send an email, see How to send email in ASP.NET C#.
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solved IEmailSender – library [closed]