var ob1 = new ConcreteObserver() { Name = "高俅", Likes = new List<string>() { "八卦" } };
var ob2 = new ConcreteObserver() { Name = "小小", Likes = new List<string>() { "科技" } };
var ob3 = new ConcreteObserver() { Name = "林三", Likes = new List<string>() { "汽车" } };

ConcreteSubject sub = new ConcreteSubject() { };
sub.Register(ob1);
sub.Register(ob2);
sub.Register(ob3);
Console.WriteLine("--------------------------------");

sub.Publish("最近好多明星结婚啦！", "八卦");
Console.WriteLine("--------------------------------");

sub.Publish("华为研发出新电池！", "科技");
Console.WriteLine("--------------------------------");

sub.Remove(ob2);
Console.WriteLine("--------------------------------");

sub.Publish("众泰出保时捷款了！", "汽车");

Console.ReadKey();

public delegate void Read(string news);

/// <summary>
/// 具体主题类 -- 今日头条
/// </summary>
public class ConcreteSubject
{
    public event Read Reads;

    public string News { get; set; }

    public void Publish(string news)
    {
        this.News = news;
        Console.WriteLine("推送主题新闻为：" + this.News);
        Reads(news);
    }
}

var ob1 = new ConcreteObserver() { Name = "高俅" };
var ob2 = new ConcreteObserver() { Name = "小小" };
var ob3 = new ConcreteObserver() { Name = "林三" };

ConcreteSubject sub = new ConcreteSubject() { };
sub.Reads += ob1.Read;
sub.Reads += ob2.Read;
sub.Reads += ob3.Read;

sub.Publish("最近好多明星结婚啦！");
Console.WriteLine("--------------------------------");

sub.Reads -= ob2.Read;

sub.Publish("众泰出保时捷款了！");

Console.ReadKey();

public delegate void Read(ConcreteSubject subject);

public class Subject{ }

/// <summary>
/// 具体主题类 -- 今日头条
/// </summary>
public class ConcreteSubject : Subject
{
    public event Read Reads;

    public string News { get; set; }

    private string category;

    public void Publish(string news, string category)
    {
        this.News = news;
        this.category = category;
        Console.WriteLine("推送新闻({0})：{1}", this.category, this.News);
        Reads(this);
    }

    public string GetCategory()
    {
        return this.category;
    }
}