Question

I have an interface with a property:

interface IFoo
{
  object Bar { get; }
}

Is there a way to instruct the implementing class, that the return value of Bar has to be a class that is serializable (marked with the SerializableAttribute)?

Answer 1

No, there is no way to force the return type of a property of an interface to be marked with SerializableAttribute.

You could consider using ISerializable, though it is not the same of course, and would force the type to implement the interface, rather than just be marked with the attribute.

interface IFoo
{
  ISerializable Bar { get; }
}