Difference between new and override

Question

Wondering what the difference is between the following:

Case 1: Base Class

public void DoIt();

Case 1: Inherited class

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Answer 1

At the first case it will call derived class DoIt() method because new keyword hides base class DoIt() method.

At the second case it will call overriden DoIt()

  public class A
{
    public virtual void DoIt()
    {
        Console.WriteLine("A::DoIt()");
    }
}

public class B : A
{
    new public void DoIt()
    {
        Console.WriteLine("B::DoIt()");
    }
}

public class C : A
{
    public override void DoIt()
    {
        Console.WriteLine("C::DoIt()");
    }
}

let create instance of these classes

   A instanceA = new A();

    B instanceB = new B();
    C instanceC = new C();

    instanceA.DoIt(); //A::DoIt()
    instanceB.DoIt(); //B::DoIt()
    instanceC.DoIt(); //B::DoIt()

Everything is expected at above. Let set instanceB and instanceC to instanceA and call DoIt() method and check result.

    instanceA = instanceB;
    instanceA.DoIt(); //A::DoIt() calls DoIt method in class A

    instanceA = instanceC;
    instanceA.DoIt();//C::DoIt() calls DoIt method in class C because it was overriden in class C