在子嵌套类c#中继承和扩展父嵌套类

public class ParentNestedClass
{
    public void ParentMethod()
    {
        Console.WriteLine("This is a method in the parent nested class.");
    }
}

public class OuterClass
{
    public class ChildNestedClass : ParentNestedClass
    {
        public void ChildMethod()
        {
            Console.WriteLine("This is a method in the child nested class.");
        }
    }
}

public static class ExtensionMethods
{
    public static void ExtensionMethod(this ParentNestedClass parent)
    {
        Console.WriteLine("This is an extension method for the parent nested class.");
    }
}

public class Program
{
    public static void Main(string[] args)
    {
        OuterClass.ChildNestedClass child = new OuterClass.ChildNestedClass();
        child.ParentMethod(); // 继承父嵌套类的方法
        child.ChildMethod(); // 子嵌套类自己的方法

        ParentNestedClass parent = new ParentNestedClass();
        parent.ExtensionMethod(); // 扩展方法

        Console.ReadLine();
    }
}