Question

Is it possible to use Resharper to refactor code such that the below method Eat is extracted into a seperate class, and the newly extracted class is injected in the Dinner class as an external dependency?

Original Code

public class Dinner
{
    public Dinner()
    {

    }

    public void Eat()
    {
        //do the eating
    }
}

Refactored Code

public interface IEatService
{
    void Eat();
}

public class EatService : IEatService
{
    public void Eat()
    {

    }
}
public class Dinner
{
    private readonly IEatService _eatService = null;

    public Dinner(IEatService eatService)
    {
        _eatService = eatService;
    }

    public void Eat()
    {
        _eatService.Eat();
    }

}

It doesn’t have to be exactly as the refactored code – this is shown to give an idea.

Answer 1

You can do it nearly as you want in R# 7 using three-step refactoring:

1. Place the caret at your Eat method, invoke Extract Class refactoring (Ctrl-Shift-R in VS), name your class EatService.
2. Place the caret at your EatService class, invoke Extract Interface refactoring.
3. Place the caret at your EatService class, invoke Use Base type Where Possible refactoring.

All that is left is to fix a constructor in Dinner class so it would get IEatService as a parameter.