C#•3y ago

Confused about interface default implementations [Answered]

Trying out default implementations for methods in the interfaces for the first time. In the interface there's a public method that if I define in a class, that class implementation is used. However, the second method is the same concept but when called, the default implementation from the interface is called instead. I found out it has to do with the method being internal instead of public but why does it work like that?

9 Replies

TheBoxyBearOP•3y ago

interface IFoo
{
  public void A() {}
  internal void B() {}
}

class Foo : IFoo
{
  public void A() {} // Always runs if the runtime type is Foo
  internal void B() {} // Doesn't run unless made public
}

interface IFoo
{
  public void A() {}
  internal void B() {}
}

class Foo : IFoo
{
  public void A() {} // Always runs if the runtime type is Foo
  internal void B() {} // Doesn't run unless made public
}

Fixed it by explicitly implementing the internal method but still curious about the logic behind it compared to public methods

333fred•3y ago

Because the CLR does not look at internal methods when considering interface implementations

Accord•3y ago

✅ This post has been marked as answered!

TheBoxyBearOP•3y ago

Kinda makes sense, interfaces are meant to be a promise about what you can do with a type. Having it internal breaks the promise

333fred•3y ago

Now that you've bumped the thread after marking it closed, you need to manually archive it @TheBoxyBear

TheBoxyBearOP•3y ago

no idea how

333fred•3y ago

Right click

TheBoxyBearOP•3y ago

Nothing about archiving in the context menu

Accord•3y ago

✅ This post has been marked as answered!

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Confused about interface default implementations [Answered]