如何使用在子类中创建的方法(不是在接口上实现的方法)| C# .NET

public class ParentClass
{
    public virtual void PrintMessage()
    {
        Console.WriteLine("This is a message from the parent class.");
    }
}

public class ChildClass : ParentClass
{
    public override void PrintMessage()
    {
        Console.WriteLine("This is a message from the child class.");
    }

    public void NewMethod()
    {
        Console.WriteLine("This is a new method in the child class.");
    }
}

public class Program
{
    public static void Main(string[] args)
    {
        ParentClass parent = new ParentClass();
        parent.PrintMessage();  // 输出："This is a message from the parent class."

        ChildClass child = new ChildClass();
        child.PrintMessage();   // 输出："This is a message from the child class."
        child.NewMethod();      // 输出："This is a new method in the child class."
    }
}