static void Main()
        {
            ForumPost_xmfish fish = new ForumPost_xmfish();
            ForumManage manage = new ForumManage();
            manage.AAA(fish, "", "", "", "", "");
}

    public class ForumManage
    {
        string title;
        string content;
        ForumPostBase catcher;


        public bool  AAA(ForumPostBase fpost, string title  ,string content, string zhanghao , string mima, string fid)
        {
            return fpost.Post(title,content,fid);
        }
    }

public class ForumPostBase
    {
        public string forumName;
        public string forumSite;

        public bool Post(string title, string content, string fid)
        {
            string aa = ""; //断点， 程序会进入这里；
            return true;
        }
    }

public class ForumPost_xmfish : ForumPostBase
    {
        public string forumName = "厦门小鱼论坛";
        public string forumSite = "www.xmfish.com";

        public virtual bool Post(string title, string content, string fid)
        {
            string aaa = "";   // 断点， 程序不会进入这， 但是我希望是执行POST方法的时候， 能到这来
            return true;
        }
    }