Question

I need to change an interface that is used by more than one app. The change is only needed for this one app I am working on. I need to add a few more parameters to the method.

I do have access to change the code in the other apps and it would only take a few minutes to change the other apps to use the correct method signature. I could then make those apps do nothing with those extra parameters.

Or I could create an overload and have the other apps implement the methods and do nothing I guess. Or have them call to the original method without the extra parameters.

What’s the best practice here, friends?

Answer 1

You can add new interface (i.e. INewInterface) implementing the old one (i.e. IOldInterface). Ane then implement the INewInterface to the class/struct.

public interface IOldInterface {
    object DoSomething( int number );
}
...
public interface INewInterface : IOldInterface {
    object DoSomething( int number, TimeSpan time );
}
...
public class MyClass : IOldInterface, INewInterface {
    public object DoSomething( int number ) { ... }
    public object DoSomething( int number, TimeSpan time ) { ... }
}