CODEWITHSUNDEEP
c#oopinheritanceinterface
Steven Wood
Steven Wood

Reputation: 2775

Interface for Child Class that Inherits from parent class without reimplementing parent class

Currently I have the following:

public class ChildClass : ParentClass
{...

ParentClass implements an interface as follows (I need ParentClass to be instantiated and therefore can't be abstract):

public class ParentClass : IParentClass
{...

I also want child class to implement an interface so that I can mock this class out, but I want the inherited members of ParentClass to be visible to the ChildClass Interface.

So if I have a method MethodA() in the parent class, I want this method to be able to be called when using IChildClass and not just ChildClass.

The only way I can think of is to override the method in the ChildClass, define that method in IChildClass and the just call base.MethodA() but this doesnt really seem correct

Upvotes: 1

Views: 2500

Answers (2)

Steve Lillis
Steve Lillis

Reputation: 3256

If I understand you correctly, you're saying that you want an inheritance hierarchy in your interfaces as well as your classes.

This is how you'd achieve such a thing:

public interface IBase 
{
    // Defines members for the base implementations
}

public interface IDerived : IBase
{
    // Implementors will be expected to fulfill the contract of
    // IBase *and* whatever we define here
}

public class Base : IBase
{
    // Implements IBase members
}

public class Derived : Base, IDerived
{
     // Only has to implement the methods of IDerived, 
     // Base has already implement IBase
}

Upvotes: 4

Steven Lemmens
Steven Lemmens

Reputation: 630

I think you can do two things.

1) You can inherit multiple Interfaces. C# supports this. You can only inherit from one base class, but you can inherit from multiple interfaces.

2) You can make your Interfaces inherit from each other. The IChildClass interface can inherit from the IParentClass interface.

Does that help?

Upvotes: 3

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