How to delete object?

Question

I need to create a method of class that delete the instance.

public class Car
{
    private string m_Color;

    public string Color
    {
        get { return m_Color; }
        set { m_Color = value; }
    }

    public Car()
    {
    }

    public void Delete()
    {
        /*This method will delete the instance,
        so any references to this instance will be now null*/
    }
}

class Program
{
    static void Main( string[] args )
    {
        Car car = new Car();

        car.Delete();

        if(car==null)
            Console.WriteLine("It works.");
        else
            Console.WriteLine("It doesn't work.")
    }
}

I want to know if there is any possible solution (even if it is not recommended) how to do this.

Instance of this class will be stored in hundreds of different class. I will try to describe this, for example there will be these classes:

public class CarKey
{
    private Car m_Car;

    public Car Car
    {
        get { return m_Car; }
    }

    public bool CarExist{ get{ return m_Car != null; } }

    public CarKey( Car car )
    {
        m_Car = car;
    }
}

public class Garages
{
     private List<Car> m_Collection = new List<Car>();

     private int m_Size;

     public int Size{ get{ return m_Size; } }

     public Garages( int size )
     {
         for(int i=0;i<size;i++)
             m_Collection.Add(null);
     }

     public bool IsEmpty( int garage )
     {
         return m_Collection[garage] == null;
     }

     public void InsertCar( Car car, int garage )
     {
          if( m_Collection[garage] != null )
            throw new Exception("This garage is full.");

          m_Collection[garage] = car;
     }


     public Car GetCar( int garage )
     {
         if( m_Collection[garage] == null )
           throw new Exception("There is no car, maybe it was deleted.");

         return m_Collection[garage];
     }
}

Answer 1

From any class you can't set its value to null. This is not allowed and doesn't make sense also -

public void Delete()
{
    this = null; <-- NOT ALLOWED
}

You need an instance of class to call Delete() method so why not set that instance to null itself once you are done with it.

Car car = new Car();
// Use car objects and once done set back to null
car = null;

Anyhow what you are trying to achieve is not possible in C#. I suspect from your question that you want this because there are memory leaks present in your current design which doesn't let the Car instance to go away. I would suggest you better profile your application and identify the areas which is stopping GC to collect car instance and work on improving that area.