I think they are advanced topics.

C#

  1. when will you use list, when will you use hashtable.

  2. when will you use Idispose.

  3.

Async and Await

public async Task<string> DoAsync5()
        {
           Task<string> mytask=Task.Run<string>(() =>
            {
                for (int j = 0; j < 20; j++)
                {
                    System.Threading.Thread.Sleep(100);
                    Console.Write("------------Async thread: " + j.ToString() + "\r\n");
                }

return "good";
            });

return await mytask;

//return "good";
            //Task.Factory.StartNew();

//IAsyncResult ar = mydoasync2.BeginInvoke(new AsyncCallback(CallbackMethod), mydoasync2);

//return result;

}

publicasyncTask<string> DoAsync()

{

Task<string> mytask = DoAsync5();

for (int i = 0; i < 100; i++)

{

System.Threading.Thread.Sleep(10);

Console.Write("Main thread: " + i.ToString() + "\r\n");

}

 

string mytaskResult = await mytask;

Console.Write("Both threads: " + mytaskResult);

return mytaskResult;

}

If you want to use await and async, you must call await twice.

1. In async function's definition.

2. In the excution funciton.

You must await a awaitable task!!!!!!

How to make a awaitable task. Define a task by task.run and await it......

It is strangely.

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("主线程测试开始..");
        AsyncMethod();
        Thread.Sleep(1000);
        Console.WriteLine("主线程测试结束..");
        Console.ReadLine();
    }
 
    static async void AsyncMethod()
    {
        Console.WriteLine("开始异步代码");
        var result = await MyMethod();
        Console.WriteLine("异步代码执行完毕");
    }
 
    static async Task<int> MyMethod()
    {
        for (int i = 0; i < 5; i++)
        {
            Console.WriteLine("异步执行" + i.ToString() + "..");
            await Task.Delay(1000); //模拟耗时操作
        }
        return 0;
    }

------------------------------------------------------------------------------------------

About begininvoker and callback.

you need to send the delegation itself to callback. If not, callback can't end this invoker correctly.

Now, there is theory and then there is practice. You have found, like
many other developers before you, that you can often get away with
ignoring this documented requirement. It may be an implementation detail
whether EndInvoke actually does anything that's absolutely
necessary to prevent your application from crashing, leaking memory,
etc. But here's the thing: if it's a documented requirement, you really ought to do it. This is not just about theory; it's about protecting yourself in the event of change.

By documenting this requirement, the designers of this asynchronous
calling mechanism basically gave themselves the freedom to change the
way BeginInvoke and EndInvoke work down the line so that, if there were sufficient reason (e.g., a performance enhancement), EndInvoke
could suddenly become a lot more necessary. Suppose it would suddenly
result in a deadlock if you forgot it. They've already covered
themselves by saying always call EndInvoke; if your app stops working because you didn't follow this requirement, the onus is on you.

I'm not saying this is necessarily a likely scenario. My point is simply that you shouldn't—or at least I wouldn't—ask "Is this really necessary?" with the mindset of If I can get away with leaving it out, then I will, since it is documented that you should do it.

http://stackoverflow.com/questions/4585042/is-delegate-endinvoke-really-necessary

Today's interview of C#的更多相关文章

  1. Pramp mock interview (4th practice): Matrix Spiral Print

    March 16, 2016 Problem statement:Given a 2D array (matrix) named M, print all items of M in a spiral ...

  2. WCF学习系列二---【WCF Interview Questions – Part 2 翻译系列】

    http://www.topwcftutorials.net/2012/09/wcf-faqs-part2.html WCF Interview Questions – Part 2 This WCF ...

  3. WCF学习系列一【WCF Interview Questions-Part 1 翻译系列】

    http://www.topwcftutorials.net/2012/08/wcf-faqs-part1.html WCF Interview Questions – Part 1 This WCF ...

  4. Amazon Interview | Set 27

    Amazon Interview | Set 27 Hi, I was recently interviewed for SDE1 position for Amazon and got select ...

  5. Java Swing interview

    http://www.careerride.com/Swing-AWT-Interview-Questions.aspx   Swing interview questions and answers ...

  6. Pramp - mock interview experience

    Pramp - mock interview experience   February 23, 2016 Read the article today from hackerRank blog on ...

  7. 【Codeforces 738A】Interview with Oleg

    http://codeforces.com/contest/738/problem/A Polycarp has interviewed Oleg and has written the interv ...

  8. [译]Node.js Interview Questions and Answers (2017 Edition)

    原文 Node.js Interview Questions for 2017 什么是error-first callback? 如何避免无止境的callback? 什么是Promises? 用什么工 ...

  9. WCF学习系列三--【WCF Interview Questions – Part 3 翻译系列】

    http://www.topwcftutorials.net/2012/10/wcf-faqs-part3.html WCF Interview Questions – Part 3 This WCF ...

  10. WCF学习系列四--【WCF Interview Questions – Part 4 翻译系列】

    WCF Interview Questions – Part 4   This WCF service tutorial is part-4 in series of WCF Interview Qu ...

随机推荐

  1. BZOJ2276: [Poi2011]Temperature

    2276: [Poi2011]Temperature Time Limit: 20 Sec  Memory Limit: 32 MBSubmit: 293  Solved: 117[Submit][S ...

  2. 32位vs2010的项目如何在64位系统上运行

    64位注册 1. 关闭Visual Studio.2. 在Visual Studio Tools目录,以管理员身份运行Visual Studio Command Prompt (2010),[注:这个 ...

  3. Sql自动生成字母加数字的随机数

    /* select char(65+ceiling(rand()*25)) --随机字母(大写) select char(97+ceiling(rand()*25)) --随机字母(小写) selec ...

  4. tinyxml开源库的基本用法

    最近项目中的某个功能需要写xml,由于项目中已经引入了tinyxml,所以不再寻找其他开源库. 前提:你得有个xml对象,声明tinyxml的对象:基于tinyxml的内存管理,TiXmlDocume ...

  5. selenium webdriver python 开始

    学习资料: Selenium with Python: http://selenium-python.readthedocs.org/en/latest/index.html 乙醇的python se ...

  6. java读XML文件

    XML文件设计为传输和存储数据,其焦点为数据内容. HTML设计为用来显示数据, 其焦点为数据外观. XML仅仅是文本文件,任何文本编辑器一般情况下都能对其进行编辑. XML没有预定义的标签,并且设定 ...

  7. 【COM学习】之一、QueryInterface

    开始先说一句,学习com之前要学好c++ 对象模型. QueryInterface的使用: QueryInterface是IUnknown的一个成员函数,客户可以通过此函数来查询某个组件是否支持某个特 ...

  8. String Format for DateTime [C#]

    This example shows how to format DateTime using String.Format method. All formatting can be done als ...

  9. Spark RDD API具体解释(一) Map和Reduce

    本文由cmd markdown编辑.原始链接:https://www.zybuluo.com/jewes/note/35032 RDD是什么? RDD是Spark中的抽象数据结构类型,不论什么数据在S ...

  10. 高效JQuery编码

    缓存变量 DOM遍历是昂贵的,所以尽量将会重用的元素缓存. // 糟糕   h = $('#element').height(); $('#element').css('height',h-20); ...