调用而不是派生基方法中的阴影

我正试图弄清楚c#中阴影的概念。这是我的代码，它没有像我预期的那样运行：

public class Animal
{
    public virtual void Foo()
    {
        Console.WriteLine("Foo Animal");
    }
}
public class Dog : Animal
{
    public new void Foo()
    {
        Console.WriteLine("Foo Dog");
    }
}
class Program
{
    static void Main(string[] args)
    {
        Dog dog1 = new Dog();
        ((Animal)dog1).Foo();
        Animal dog2 = new Dog();
        dog2.Foo();
    }
}

当执行Main中的代码时，来自基类（Animal）的Foo()将被调用，根据我所读到的关于阴影的内容，应该调用来自Dog的Foo()。有人能解释一下我遗漏了什么吗？

我的例子是这样的：https://msdn.microsoft.com/en-us/library/ms173153.aspx

更新：这是msdn:中的示例

class Program
{
    static void Main(string[] args)
    {
        BaseClass bc = new BaseClass();
        DerivedClass dc = new DerivedClass();
        BaseClass bcdc = new DerivedClass();
        // The following two calls do what you would expect. They call
        // the methods that are defined in BaseClass.
        bc.Method1();
        bc.Method2();
        // Output:
        // Base - Method1
        // Base - Method2

        // The following two calls do what you would expect. They call
        // the methods that are defined in DerivedClass.
        dc.Method1();
        dc.Method2();
        // Output:
        // Derived - Method1
        // Derived - Method2

        // The following two calls produce different results, depending 
        // on whether override (Method1) or new (Method2) is used.
        bcdc.Method1();
        bcdc.Method2();
        // Output:
        // Derived - Method1
        // Base - Method2
    }
}
class BaseClass
{
    public virtual void Method1()
    {
        Console.WriteLine("Base - Method1");
    }
    public virtual void Method2()
    {
        Console.WriteLine("Base - Method2");
    }
}
class DerivedClass : BaseClass
{
    public override void Method1()
    {
        Console.WriteLine("Derived - Method1");
    }
    public new void Method2()
    {
        Console.WriteLine("Derived - Method2");
    }
}

当执行bcdc.Method1()时，会调用派生类中的Method1()，而在我的示例中并非如此。