public class ProxySubject : ISubject
{
    //组合一下
    private static ISubject _Subject = new RealSubject();
    public void DoSomething()
    {
        try
        {
            Console.WriteLine("prepare DoSomething...");
            _Subject.DoSomething();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            throw ex;
        }
    }
    private static Dictionary<string, bool> ProxyDictionary = new Dictionary<string, bool>();
    public bool GetSomething()
    {
        try
        {
            Console.WriteLine("prepare GetSomething...");
            string key = "Proxy_GetSomething";
            bool bResult = false;
            if (!ProxyDictionary.ContainsKey(key))
            {
                bResult = _Subject.GetSomething();
                ProxyDictionary.Add(key, bResult);
            }
            else
            {
                bResult = ProxyDictionary[key];
            }
            return bResult;
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            throw ex;
        }
    }
}

/// <summary>
/// 一个耗时耗资源的对象方法
/// 一个第三方封装的类和方法
/// </summary>
public class RealSubject : ISubject
{
    public RealSubject()
    {
        Thread.Sleep(2000);
        long lResult = 0;
        for (int i = 0; i < 100000000; i++)
        {
            lResult += i;
        }
        Console.WriteLine("RealSubject被构造。。。");
    }
    /// <summary>
    /// 火车站查询火车票
    /// </summary>
    public bool GetSomething()
    {
        Console.WriteLine("坐车去火车站看看余票信息。。。");
        Thread.Sleep(3000);
        Console.WriteLine("到火车站，看到是有票的");
        return true;
    }
    /// <summary>
    /// 火车站买票
    /// </summary>
    public void DoSomething()
    {
        Console.WriteLine("开始排队。。。");
        Thread.Sleep(2000);
        Console.WriteLine("终于买到票了。。。");
    }
}

 {
     Console.WriteLine("***********Real**************");
     ISubject subject = new RealSubject();
     subject.GetSomething();
     //subject.DoSomething();
 }
 {
     Console.WriteLine("***********Proxy**************");
     ISubject subject = new ProxySubject();
     subject.GetSomething();
     //subject.DoSomething();
 }
 {
     Console.WriteLine("***********Proxy**************");
     ISubject subject = new ProxySubject();
     subject.GetSomething();
     //subject.DoSomething();
 }