Question

I have this piece of code:

public List<IVehicle> Vehicles { get; private set; }

My question is even though i am using a private set, why i can still add values to this list.

Answer 1

When use use a private set what that means is that the property itself is un-setable from outside the class, not that it’s methods are not available, and List<T>.Add() is only a method that the compiler knows nothing about.

By example:

public class VehicleContainer{
   public List<IVehicle> Vehicles { get; private set; }
   ...
}
....
VehicleContainer vc = new VehicleContainer();
vc.Vehicles  = new List<IVehicle>() // this is an error, because of the private set
int x = vc.Vehicles.Count; // this is legal, property access
vc.Vehicles.Add(new Vehicle()); //this is legal, method call

Take a look at this question, where use of the ReadOnlyCollection class is explained in the case when you want to restrict access to the collection itself, as well as the reference to the collection.