到底会call哪个Test method呢？欢迎讲出原因！
class Program
    {

        static void Main(string[] args)
        {

            DerivedClass dc = new DerivedClass();
 

            int i = 5;
            dc.Test(i);
            ((BaseClass)dc).Test(i);

            Console.ReadLine();
        }
    }
 

public class BaseClass
    {

        public virtual void Test(int i)
        {
            Console.WriteLine("BaseClass.Test(int i)");
        }
    }

    public class DerivedClass : BaseClass
    {
        public override void Test(int i)
        {
            Console.WriteLine("DerivedClass.Test(int i)");
        }
 
       public void Test(double i)
        {
            Console.WriteLine("DerivedClass.Test(double i)");
        }

    }