Question

I have an interface and a class that implements that interface.

I have a requirement that the class has a dependency on ITimer. A private member is created and a constructor argument is passed in and the private member is assigned to that constructor parameter.

How do I make it so that the interface has this ITimer declared somehow but not as a property? Its not as if I can’t test MyClass properly but I thought the interface was supposed to be a contract that the class must adhere to therefore my class has a dependency so how do I make this appear in the interface?

public interface IMyInterface
{
  void DoSomething();
}

public class MyClass : IMyInterface
{
  private ITimer MyTimer;

  public MyClass(ITimer timer)
  {
    MyTimer = timer;
  }

  public void DoSomething()
  {

  }
}

Answer 1

This cannot be done with an interface in C#. What you could do is to inherit from an abstract class instread of an interface.

public abstract class AMyClass
{
  protected ITimer MyTimer;

  public AMyClass(ITimer timer)
  {
    MyTimer = timer;
  }

  public abstract void DoSomething();
}

public class MyClass : AMyClass
{
  public override void DoSomething()
  {

  }
}