Question

I have 2 classes, each returns itself in all of the function:

public class Parent{
   public Parent SetId(string id){
      ...
      return this
   }
}

public class Child : Parent{
   public Child SetName(string id){
      ...
      return this
   }
}

I want to enable this kind of API:

new Child().SetId("id").SetName("name");

SetName cannot be accessed since SetId returns Parent and SetName is on the Child.

How?

Answer 1

If you really want this fluent behavior, and the Parent class can be made abstract, then you could realize it like this:

public abstract class Parent<T> where T : Parent<T>
{
    public T SetId(string id) {
        return (T)this;
    }
}

public class Child : Parent<Child>
{
    public Child SetName(string id) {
        return this;
    }
}

It is now possible to write:

new Child().SetId("id").SetName("name");