Derived and base class, can I set the base explicitly?

Question

public class SuperCar: Car
{
     public bool SuperWheels { get {return true; } }
}

public class Car 
{
     public bool HasSteeringWheel { get {return true;} }
}

How can I set the base class for the derived Supercar?

For example, I want to simply set SuperCars base class like this:

public void SetCar( Car car )
{
SuperCar scar = new SuperCar();
car.Base = car; 
}

Basically, if I have Car objects, I do not want to manually iterate through every property of the car in order to setup the SuperCar oject, which I think is the only way you can do it but if you can do it the other way it would be sooo much better.

Answer 1

I use something like this in the subclass and it works fine for me:

using System.Reflection;
.
.
.
/// <summary> copy base class instance's property values to this object. </summary>
private void InitInhertedProperties (object baseClassInstance)
{
    foreach (PropertyInfo propertyInfo in baseClassInstance.GetType().GetProperties())
    {
        object value = propertyInfo.GetValue(baseClassInstance, null);
        if (null != value) propertyInfo.SetValue(this, value, null);
    }
}

Answer 2

If I'm understanding your question correctly (and I'm not entirely sure that I am), then you can sort of get the behavior you want by doing something like this:

class Car {
    public bool CarProperty { get; set; }
    // regular constructor
    public Car() {

    }
    // "copy" constructor
    public Car(Car c) {
        CarProperty = c.CarProperty;
    }
}

class SuperCar : Car {
    public bool SuperCarProperty { get; set; }
    // regular constructor
    public SuperCar() {
    }
    // "copy" constructor
    public SuperCar(Car c) : base(c) {
        SuperCar sc = c as SuperCar;
        if(sc != null) {
            SuperCarProperty = sc.SuperCarProperty;
        }
    }

Then you can do this:

public void SetCar(Car car) {
    SuperCar scar = new SuperCar(car);
}

Note that you have to be very careful in your "copy" constructor not to copy properties in such a way that two objects share the same members (references) when they should not.

I have to ask, though, what your goal is with this?

Answer 3

This is not possible.

You need to manually set the properties.

Answer 4

You can only copy the contents of another class, but not set it directly. See example below using what is called a copy constructor.

class Car
{
    string model;
    public Car(string model) { this.model = model; }
    protected Car(Car other) { this.model = other.model; }
    string Model { get; set; }
}

class SuperCar : Car
{
    public SuperCar(Car car) : base(car) { }
    public SuperCar(string model) : base(model) { }
    bool IsTurbo { get; set; }
}

The key is the keyword base() after the constructor declaration.

Answer 5

Overall a lot of helpful comments. I think the short answer was given by pst and I think this is correct:

No. Short reason: There is no separate base object. (object)this == (object)base is always true. There are ways to perform cloning/copying by reflection (and other means) though. Perhaps describe what is really wanted

So, his suggestion of using the automapper tool was also incredibly useful and was basically what I was looking for.