You can be a Certified Kubernetes Application Developer too!

What is CKAD

The Certified Kubernetes Application Developer (CKAD) program has been developed by the Cloud Native Computing Foundation (CNCF), in collaboration with The Linux Foundation, to help expand the Kubernetes ecosystem through standardized training and certification. As one of the highest velocity projects in the history of open source, Kubernetes use is exploding.

Why CKAD

The Cloud Native Computing Foundation is committed to growing the community of Kubernetes-knowledgeable application developers, thereby enabling continued growth across the broad set of organizations a using the technology. Certification is a key step in that process, allowing certified application developers to quickly establish their credibility and value in the job market, and also allowing companies to more quickly hire high-quality teams to support their growth.

Once I learned that CKAD is all hands on labs, it immediately caught my attention for serveral reasons:

• Challenging than multiple choice
• A certificate that not many have obtained so far
• Microsoft Loves opensource and I love Kubernetes

Preparation #1

I didn't prepare much, I thought i'm good at exams! Ok, I was, I ranked 4th out of 140,000 students in college entrance exam but I clearly forgot how I achieved that. I thought I know kubernetes well, both as an architect and as a developer, I've read books, and have plenty of hands on POC built, and worst scenario, I have a free retake exam even if I failed. So I booked the exam and took it.

I did however googled a few prep exercise and "looked" at it. All those commands look familiar and simple, I can do it... Thought swimming is simple by just looking, correct? Big mistake here.

https://github.com/dgkanatsios/CKAD-exercises

Yes, I failed my first exam... 55%... need 66% to pass, and I was very close, I just didn't have enough time, After 1h 40 minutes, I realise I just finished a little bit over half of the questions. I had a panic attack. Some of the questions were easy but I often missed a bit of here and there, resulting in debugging that is time consuming...

Preparation #2

I learned the lesson, I need to practice. It took about 2-3 days very intense practise. That's it, no tips, just practise all the questions here. There are some duplicates, but does that matter, it just means practise twice. Total of 300 questions. If you can do these (not in your head) in a cluster, you can do the exam.

https://github.com/dgkanatsios/CKAD-exercises

https://medium.com/bb-tutorials-and-thoughts/practice-enough-with-these-questions-for-the-ckad-exam-2f42d1228552

Familiarise myself with all the tasks and tutorials in the official https://kubernetes.io webiste. I had O'Reilly subscription which give me a sandbox Kubernetes environment in a few clicks and I can practise whenever I want.

I used all the tips that was mentioned in the articles listed below, and here are few of mine that you won't find anywhere else:

• Before the exam starts, use the notebook to write down 1 to 19. When the exam starts and you start to solve problems, you can write the point % next to the number, as well as if you are 100% confident, or need to review, is it hard or is it time consuming, or simply passed because it doesn't worth much.
• 20 minutes before the exam finishes, have a look at your notebook and decides which problem gives you the best bang for bucks. You should be able to solve 3 problems in 20 minutes, and get those that offer best points for time.
• Use a direct command instead of declarative definition, but save the yaml to q_id.yaml file so you can always go back to edit it.
• If you know how to validate, i think it is still worse validate your solution. However, you need to be very fast!
• Take the exam and you will see the need to practise, then take the retake like me :)

I passed the exam with 92% the second time. The question is different to my first attempt but do share some similarity. Admittedly I didn't even see all the questions from my first attempt. I finished all the questions, probably most in the first 1h30 minutes. I have confident that they are all correct as i run command against to validate the results. I'd say it is a very simple exam if you practise.

Final tips

Linux foundation is running a 30% discount promotion so secure your exam today and you can take that in the next 12 months! Offer ends 7th April.

Other articles you should read to better prepare CKAD

Follow-up after passing the exam 

Ultimate guide to passing CKA 

CKAD Tips

CKAD Tips & Tricks

Everything You Need to Know About the CKA and CKAD 

My way to pass CKA (Certified Kubernetes Administrator) and CKAD (Certified Kubernetes Application Developer) Exams

So you’ re taking your CKA exam

Tips to pass Certified Kubernetes Application Developer (CKAD) exam

How to finish the Kubernetes Certification Exam in time

CKAD exam tips 

How to ace the CKA in 7 days 

Reddit thread dedicated to CKA 

How to finish the Kubernetes Certification Exam in time

Kubernetes CKAD weekly challenge #1 Creating Pods 

Kubernetes CKAD weekly challenge #2 Namespaces, Deployments and Services 

Docker inspect image content tricks

Sometimes one might wonder what exactly the image looks like once run as a container. This is particularly useful for debugging. 

Docker run command help us solve this problem. 

docker run -it --rm to do two things, first, automatically use the current terminal to connect to the container, and then when the container finishes, remove it.  Now we change the entry point to use bash (or cmd.exe for windows containers).

c:\Docker>docker run -it --rm --entrypoint "bash" reposit:v4
root@35b518b7b518:/home/reposit# ls
data  node_modules  package-lock.json  package.json  repositConnector.js
root@35b518b7b518:/home/reposit#

Export Azure DevOps TFVC repo to Github

Step 1:

Azure TFVC Repo -> Azure Git Repo 

https://docs.microsoft.com/en-us/azure/devops/learn/git/migrate-from-tfvc-to-git

Step 2:

Azure Git Repo -> GitHub

1. Enable alternate authentication credentials and specify user name and password
2. Go to a repository of your project (Code=>Files), click Clone to get the HTTPS URL.
3. Go to Github=>Import repository
4. Type repository URL (step 2)
5. Type alternate authentication credentials (step 1) when it asks for credential

https://developercommunity.visualstudio.com/content/problem/449985/export-devops-repos-to-github.html

Microsoft.SqlServer.Management.SMO

Hi All,

I’ve been using SMO heavily in my OSR data migration piece of work, and I’d like to share that with you.  To put SMO into context, I consider it as a programmatic way to interact with SSMS.

For CRUD actions, SqlClient is still very good. Very flexible compared to entity framework.

However, when we need extra flexibility, e.g., create/backup database, create/alter tables, especially running SQL with GO statement, SMO is the way to go.   

I’ve attached a Util class that demonstrates how it can be wrapped, and the dynamic SQL that gets generated by my program and executed via the Util class.

If you would like to know more, plenty of articles on MSND:

SQL Server Management Objects (SMO) is a collection of objects that are designed for programming all aspects of managing Microsoft SQL Server

http://msdn.microsoft.com/en-us//library/ms162169.aspx

Sqlserver nvarchar ntext difference

Thanks to Graeme for asking an interesting question about the difference between nvarchar and varchar. Since my first language can’t be stored in ACSII, I know nvarchar is the way to go.

Further reading on nvarchar(max) prompted us to think the differences between nvarchar and ntext, and we found the following in MSDN. 

ntext , text, and image data types will be removed in a future version of Microsoft SQL Server. Avoid using these data types in new development work, and plan to modify applications that currently use them. Use nvarchar(max), varchar(max), and varbinary(max) instead.

Don’t panic, further version doesn’t include SQLServer 2012.  Read more here:

http://msdn.microsoft.com/en-us/library/ms187993.aspx

.Net Entity Framework and DAL

This old post demonstrates some very interesting thoughts about DAL and Entity Framework, and discussed the design pattern (pros and cons) in an architecture point of view. At the last of this post, a ppt is embedded. http://www.wadewegner.com/2009/06/architecting-your-data-access-layer-with-the-entity-framework/

Here are some highlights and my understanding:

·         Use EF as DAL  This is still a good option to replace the CRUD. See my OpsLog comments below about EF.
·         Full Encapsulation of the Entity Framework.  This is the ideal solution but we probably won’t get to the complexity. It reduces coupling and make application testable.
·         Partial Encapsulation of the Entity Framework.  The author didn’t give an example, but I have some in EGMAN.  EGMAN uses MVC and MVVM (MVVM Model-View ViewModel is similar to MVC, Model-View Controller).  I used EF to map db to model (M in MVC), but sometimes lost the flexibility to add custom attribute and data access logic. I adopted MVVM, which use VM to replace C, and VM is the encapsulation of EF that extract data from the Model. 

Links of the Month November

OpenXML: New and easiest way to do handle MS Office document on server (eg, mailmerge)
·         Example: TFS $ActewAGL.MailMerge
·         Download: http://www.microsoft.com/en-us/download/details.aspx?id=5124
·         Read More

Asp.NET MVC: A mindset change to build testable website
·         Office Website with very good tutorials
·         Sample website with 200+ pages of step by step guild on how to build the website, MVC Music Store
LINQ:  Jon Skeet re-implement LINQ in 45 posts. Download the ebook and learn.
Tools
·         Telerik Extensios for ASP.NET MVC: free open source controls for MVC. Every control come with full sample code and demo.
·         .Net Demon: Tool that build as you type
·         NCrunch similar to .Net Demon, but also do continuous testing.
·         Both tools Combine with LiveReload (and Chrome extension), No more F6 to build, and F5 to refresh
·         VS 2012 & TFS 2012 update 1 released.  Visual Studio 2012 Update 1 focuses on enhancements to SharePoint development, Windows development, continuous quality enablement, and tools for agile teams.
·         Together with update 1 release, MS also released VS2010 Application Lifecycle Management Virtual Machine and Hands-on-Labs.  It’s really time to upgrade!
Latest
·         I won’t tell you what this is, you so have to click to find out. http://www.microsoft.com/australia/ws2012xbox/
·         Announcing the Latest Release of Office Developer Tools
·         Video:  Bleeding edge ASP.NET: See what is next for MVC, Web API, SignalR and more…
·         Microsoft Releases SkyDrive SDKs for .NET, Windows Phone 8
·         HTML5 and Why Developers Need It (IE8 support 0% of its’ feature)
·       Finally: Windows (Phone/Tablet) 8 : Too many posts out there

scrum

     After three days of training on scrum, I'd like to share few tips and materials.

Scrum is simple to understand, hard to implement. It is the most popular agile methodology. Few things I like about it:

* Daily Scrum (also referred as daily stand-up, but what if Zhen broke his knee and can't stand):  is a good way to synchronise between team members. It is not a free form, and 3 questions are answered by every team member.  (was working, plan to work, any impediment)

* Retrospective: is the best part in my opinion. Every team member answer three questions, what went well, want went wrong, how to improve. The lecture said he used this to coach his kids soccer team :)

* Working in the order of priority, and deliver business value in each sprint. 

Links of the Month October

MEF
·         Managed Extensibility Framework (MEF)
·         MEF An interesting documentation with examples
·         MEF vs IoC

Working with Data
·         Overview of Data Development platform in .Net

Tools
·         LinqPad A combination of c# and SMSS
·         Database Comparison Tool:  DBComparer
·         TFS2012 Reasons to Upgrade
Latest
·         Team Foundation Service is Released   A version of Team Foundation Server hosted on Windows Azure. Free for MSDN subscribers!
·         When JavaScript is unmanageable: Introducing Typescript
·         Typescript - a real world story of adoption in TFS 160K line of JavaScript
·         Key Windows 8 Developer Tenets and Skills

.Net tools

• ·         NuGet Package Manager: NuGet is a Visual Studio extension that makes it easy to install and update third-party libraries and tools in Visual Studio. You can install all of the library discussed here from within NuGet
• ·         AjaxControlToolkit:  http://www.asp.net/ajaxlibrary/AjaxControlToolkitSampleSite/ An open-source project built on top of the Ms ASP.NET AJAX framework. It contains more than 30 controls that enable you to easily create rich, interactive web pages. Eg, Calendar, ModalPopup, AsyncFileUpload
• ·         ELMAH: Error Logging Modules and Handlers is an application-wide error logging facility that is completely pluggable. Tutorial: http://www.asp.net/web-forms/tutorials/deployment/deploying-web-site-projects/Logging-Error-Details-with-ELMAH-cs
• ·         JQuery, JQuery UI & plugins,: More than 55% of the world most visited 10000 website use JQuery. Why shouldn’t we use it?
• ·         Json: JavaScript Object Notation is a text format, lightweight data-interchange format. A Fat-Free Alternative to XML.
• ·         Json.NET: Json.NET is a popular high-performance JSON framework for .NET. see http://james.newtonking.com/pages/json-net.aspx for details.
• ·         EF:

o   Microsoft product, we know what is means.

o   Highly Supported and plenty of resources online, with fairly strong communities online. Evolving very fast, fixes was coming out very fast and it was getting better day by day.

o   LINQ.  No more CRUD.

o   Lower learning curve than Nhibernate.

o   Desired features listed here  http://data.uservoice.com/forums/72025-ado-net-entity-framework-ef-feature-suggestions

o   Database Frist has more features than Code First

o   Easy to code and maintain compared to Dataset

Links of the month September

Microsoft Developer Links of the Month

·         Debug production system: Visual Studio Ultimate 2012: Collecting and analyzing data in production
·         TFS put into good use: Automated Build-Deploy-Test using TFS 2012
·         Visual Studio New features: Visual Studio 2012: Did You Call Me?
·         Reason not to test? None: Testing for Continuous Development
·         ASP.NET improvements continue: Introducing ASP.NET FriendlyUrls - cleaner URLs, easier Routing, and Mobile Views for ASP.NET Web Forms and ASP.NET 4.5 ScriptManager Improvements in WebForms
·         Windows Azure new features: Meet the New Windows Azure and a follow up article Announcing: Great Improvements to Windows Azure Web Sites
·         Win8: Reasons Why You Should Develop a Windows 8 App
·         Webcast: How Google Tests Software & Getting Started with Windows Azure

Want something Free?

Programming Windows 8 Apps with HTML, CSS, and JavaScript (Second Preview)

Building Hybrid Applications in the Cloud on Windows Azure

Great Free Courses on Building HTML5 apps using ASP.NET Web API, Knockout.js and jQuery

How to check a process or program is running via powershell script

Powershell script to check if a program is running or not

$Prog = "C:\Program Files (x86)\Mozilla Firefox\firefox.exe"
$Running = Get-Process firefox -ErrorAction SilentlyContinue
$Start = {([wmiclass]"win32_process").Create($Prog)}
if($Running -eq $null) # evaluating if the program is running
{& $Start} # the process is created on this line

What is a successful project 何为成功的项目

When a client receives what he's been expecting, on time and for the estimated amount of money.

Project managers define this as: On Time, On scope and On budget.

"A successful project is where everyone involved is happy with the final outcome."

以上讲的是对成功项目的定义，说白了就是客户满意，觉得钱花的值。那有些什么事情会让客户觉得不爽呢？ 没有按时，按量，按价把项目做出来，客户自然就不爽了。而速度、质量、价格三者本来就很难都保证，保证俩项，第三项势必就要有折扣，所以在谈项目的时候，应该充分考虑到三个基本要素，来报价。

The promise of a successful project is something we all work harder to achieve, but working harder is not the answer. Software companies need to work smarter before, during, and after development, to ensure that the client gets not only what they want, but what they need.

是不是死磕就能把项目搞好呢？ 死磕能加大成功的概率，但是大家都是聪明人，从小比咱们死磕的人多的去了，但大多没咱们屌，一个原因就是用的方法不对。事半功倍这个道理在软件开发中一样通行。 给客户做项目，不是你做的自己觉得多屌就好的，也许技术屌，但客户用不上；或者东西做的复杂，但客户希望简单明了。多和客户沟通，而不是一味闷头干，也许成功概率更大。

讲回正题。没有规矩不能成方圆，开发软件也是一样。那么除了开发上的规矩，还有一些做项目上的规矩，大家又知道多少呢，等我一一道来。

1. Do you understand the value of consistency?

一致性，就是说做事情不要没事就换个花样。咱们如果今天开发用MFC，明天突然就改.Net了，后台就非要再玩玩Java，就过了。 一致性能保证产出，且每次质量不断提高。 从小一点的角度来看，程序里面也需要一致性。今天造个轮子，明天用一个库，都是不好的。不仅要自己的产品一致，公司内部一致，更要和高质量主流产品一致。例子我以后都拿.net说了。Microsoft Application Block，里面的轮子咱们如果常用，就可以提高效率，保持软件质量一致性。

2. Do you know that Rules are made for the guidance of wise men and the obedience of fools?

规矩是给聪明人用的，如果你觉得规矩不对，可以提出更好的改进。

3. Do you manage clients expectations?

客户的期望是需要我们提前打预防针的。 有几点需要注意的

• 谈价钱的时候不要给区间。 你跟我说20-30w，也许客户的期望就奔着20w去了，30w就变耳边风了。而我们自己是啥意思呢，也许20w压根就没戏。
• 软件是会有bug的，所以见下一条
• 不要签固定价格的合同。 固定价格，保证没有bug?没可能嘛。所以得有个事后维护的费用，比如小时收费。开始额外收费钱，得让客户签收已有的成果。
• 早点开始谈钱。谈完了客户就有预期了。收钱也得勤快。阶段性的收，阶段可以小一点。客户给钱总归都是不爽快的，收的勤快一点，客户还知道你在干活，达到了一个里程碑。不然突然一次收一大笔，让人肉痛。

4. Do you pursue short or long-term relationships with clients?

文中的建议是短期为妙。 对待客户，可以像对待一个长期的合作伙伴一样，但是做生意的时候，还是要步步为营。不要一次跟人说：“这个项目我们100w搞定”， 而是说：“你可以花5k，我们给你安排3个程序员一周时间来调查，给你做一个报告”。给客户以选择，也是给自己更大的机会。

5. Management - Is your client clear on how you manage projects?

这里讲的是和客户沟通项目管理方法。 以敏捷开发为例子，就需要客户的积极参与。这里面，由于管理方法的不同，会导致报价，合同方面的不同。 比如说客户想要一个软件，而我们告诉客户，我们用的是敏捷开发方式，所以你那边会派出人来参与项目，需求也可能会经常改变，我们可以估价一个到某一个阶段的价，然后后面根据进度来调整。 IT开发里面fix price的这种在鬼子这里真的很少见，除非合同额巨大，10M，20M，狮子大开口，不然都必然是会由于项目调整而进度资源调整。如果能尽量减少自身风险，同时让客户得到他们需要的软件，鬼子的这种分阶段报价方式可以值得参考。

bbs特色词汇

小钻风
原是西游记里的巡山小妖的名字. 这里是为公共站务ID mitbbs起的外号。此ID刚刚由walklooktalk在sysop版公布时，大家决定叫它总钻风，因为其职能类似于总版主，但小钻风这个名字最后沿用了下来。这个ID由walklooktalk在北京的雇员轮流值班，为提高论坛流量而到各版挑选文章置顶，也经常越过各版版主处理版务，由此引起很多怨言。但由于是雇员，从不像其他站长一样耍态度。

LD
领导，一般指配偶，引申出小LD，指家里的孩子。

LP、LG
老婆、老公的简称。

WSN
Family版经常出现的称呼.可男可女.猥琐男或者猥琐女的简称.特点是心理幼稚但是不阴暗, 行为诡异但是不偏激。

外F女
外嫁女的贬义用法，F估计代表英文Fuck，原指海外华人中对洋人盲目推崇进而随便与其上床的女生，后泛指因为绿卡或金钱等不纯目的而找洋人做男友或老公的中国女子，通常在Dreamer版上出现。这个词应该是源于对一些外嫁女子在网上炫耀自己的涉外爱情和家庭经历，而引起某些人群的不平。

坑
意等同于英文词"TROLL",泛指那些投人所好有争议/夸大其词/或者纯属编造的贴子,来引发网友讨论,这样的贴子常被人称为"坑",发此类贴子的行为被称为"挖坑"。

发包子
凡文章获得版主加精 (M上)，发文用户自动获得10元伪币。借此，网友们管发文章让版主加精为发包子行为，一个包子等于10伪币。

毛上、搞上
毛上指的是版主将版面的文章mark以保留该文章，标记符号为m，故取其谐音称为毛上；而搞上是指版主将版面文章加入文摘区，标记符号为g，故取其谐音称为搞上。

饭米粒
特指“我爱我家”版（FAMILY的谐音读法）。

离
饭米粒版对婚姻问题的标准回复，后来范围扩展至所有问题。很多id上来不看文章，照着原贴就是一个字“离”。后来版主StoryTeller试图令行禁止，成效不大。

八区
泛指"中国新闻"(CHINANEWS),"世界新闻"(WORLDNEWS),以及SALON,HISTORY,MILITARY等等版面,八区的叫法源于这些版面最初在TELNET界面下统属第8版块,该版块因涉及时事新闻较多,持不同见解的人言词激烈,很多时候八区版面火药味浓重,易引发争吵,"八区"在不少网友眼中常常被视为吵架的地方。

BT
源于拼音"变态"。起初用于自认为正常人类对被认为非正常人类的蔑称. 此称谓最初出现于mitbbs dreamer版2000年左右，那个时候dreamer风格转换,忧郁的文青正在被一些被称为新生代变态的新ID为首的新成员所代替。后来这个词逐渐在 MITBBS被泛化，现在已经变成英语里面"dude"一样的称呼。BT 也指 Balance Transfer 多用于Money版。

88一下
即八卦一下。

PENG
源于"肚皮舞运动"(Joke)版面,该用法源于大约1999年左右的一则新闻：英国陆军因为军费缺乏，打靶演习无法用实弹，只好在射击时口中发出射击声音。ID katy时任Joke斑竹，并转载了该新闻，建议今后见到老笑话就用"Peng"表示。"PENG"一词后扩散至整个BBS,涵盖面也扩大到任何性质的贴子,不仅仅只是笑话贴,包括贴子是重复的或者某人说过同样的话,都可以用PENG来表达。后来在 情爱幽幽（Love）版继续演化为 “BENG”。

奔
最初称为裸奔。一般是指网友在版面上帖出自己的照片供大家欣赏取乐，有时也有如交友等特殊目的。常用的口号有：某某奔一个！奔上十大！你小你先！ 等等. 2003-2004年度裸本成为mitbbs维护人气的一个重要节目,前著名女光棍，资深ID Janet曾制作并且不定期发布裸奔大全。

晒
指专门show东西物件的，照片里没有人物只有物品。

胖子
Shopping（购物版）的常用词汇，指购物的时候使用的折扣券。因为美国商店的折扣券，英文为“Coupon”和中文“酷胖”或“哭胖”谐音，久而久之网友就改称之为“胖子”，而且显得更加琅琅上口。

死呆婆
美国著名办公用品商Staples的中文谐音，源自Mitbbs人气大版Shopping。该店因良好的客户服务、遍及美国城乡的销售网络、以及诸多的促销活动而深受Shopping版网友的推崇，某些网友的第一桶金即出自Staples。Staples目前已进入中国市场，其中文官方译名为“史泰博”。

RenPinWenTi
人品问题（rpwt）的另类表达。mitbbs南来北往，网友众多，模糊拼音的使用受到广大网友的普遍好评。

医院
ebay, 鉴于购物天堂（Shopping)版版主禁止在版上讨论ebay买卖，所以大家用“医院”这词代替ebay。典故出自前任汽车版主，shopping版资深ID coven在shopping版用隐晦的语言讲述自己在ebay因做托被封杀id及株连马甲的故事。另外由于ebay鱼龙混杂，故又用厕所一称呼代替。

病人
ebay 购物者

JHQ
精华区，多用于提示新手参考精华区，而不是一味问问题。

buffet deal (简称 buffet)
ebiz版 形容一笔交易的利润的量词。。。指获利，够享用一顿buffet...非常形象。

BSO
Bloodly Show off 不管人说啥都可以re：bso!）

c# create and write to excel file

Following my previous post c# how to read write excel spreedsheet and C# quit excel appliction after using COM objectI wanted to continue the topic with a focus on write to excel spreedsheet.

Using Microsoft.Office.Interop.Excel is the easiest option and with Excel 2007 installed, you can get version 12 of this dll. It allows user to save files as Excel 2007 format, or the old 97-03 format.

Firstly, Let’s look at some sample code.

        private static void NAR( object o )
        {
            try
            {
                System.Runtime.InteropServices.Marshal.ReleaseComObject( o );
            }
            catch( Exception ex )
            {
                Console.WriteLine( ex.ToString( ) );
            }
            finally
            {
                o = null;
            }
        }

        public override void save( FileWriter writer )
        {
            string filename = writer.FileName;

            TimeSeries[] series = checkCompatibleTimeSeries( (Data[])data.ToArray( typeof( Data ) ) );
            int count = series[0].itemCount( );
            if( count == 0 )
                throw new DataFileIOException( this, "Time series to save to " + filename + " are empty" );

            // Instantiate Excel and start a new workbook.
            Excel.Application objApp;
            Excel._Workbook objBook;
            Excel.Workbooks objBooks;
            Excel.Sheets objSheets;
            Excel._Worksheet objSheet;
            Excel.Range range;

            objApp = new Excel.Application( );
            objBooks = objApp.Workbooks;
            objBook = (Excel._Workbook)( objBooks.Add( Missing.Value ) );
            objSheets = (Excel.Sheets)objBook.Worksheets;
            objSheet = (Excel._Worksheet)( objSheets.get_Item( 1 ) );

            if( objSheet == null )
            {
                throw new Exception( "Worksheet could not be created. Check that your office installation and project references are correct." );
            }

            try
            {
                ( (Excel.Range) objSheet.Cells[ 1, 1 ] ).set_Value( Missing.Value, "Date" );
                ( (Excel.Range) objSheet.Cells[ 1, 2 ] ).set_Value( Missing.Value, filename );


                for( int rowIndex = 0; rowIndex < count; rowIndex++ )
                {
                    ( (Excel.Range) objSheet.Cells[ rowIndex + 2, 1 ] ).set_Value( Missing.Value,
                                                                                   series[ 0 ].timeForItem( rowIndex ) );

                    for( int columnIndex = 0; columnIndex < data.Count; columnIndex++ )
                    {
                        ( (Excel.Range) objSheet.Cells[ rowIndex + 2, columnIndex + 2 ] ).set_Value( Missing.Value, 
                                                                                                     series[ columnIndex
                                                                                                         ][ rowIndex ] );
                    }
                }
                objApp.DisplayAlerts = false;
                objApp.AlertBeforeOverwriting = false;
                objBook.SaveAs( filename, format , Missing.Value, Missing.Value, Missing.Value, Missing.Value,                              Excel.XlSaveAsAccessMode.xlShared, Excel.XlSaveConflictResolution.xlLocalSessionChanges, Missing.Value, Missing.Value,                               Missing.Value, Missing.Value );

                objBooks.Close( );
                objApp.Quit( );
            }
            catch( Exception theException )
            {
                throw theException;
            }
            finally
            {

                if( objBooks != null )
                    objBooks.Close( );
                if( objApp != null )
                    objApp.Quit( );
                NAR( objSheet );
                NAR( objSheets );
                NAR( objBooks );
                NAR( objBook );
                NAR( objApp );
            }

            GC.Collect( );
            GC.WaitForPendingFinalizers( );    

        }

Some tricky part of the code is the SaveAs Method. In order to disable the pop up alert messagebox, you need to do few things. (I believe most people do want to disable it since this must have been handled in the GUI part). Excel.XlSaveAsAccessMode.xlShared is the essential key to solve this problem. If it is not used, then  Excel.XlSaveConflictResolution.xlLocalSessionChanges wouldn’t work. Both “objApp.DisplayAlerts = false;” and “ objApp.AlertBeforeOverwriting = false; ” are used in the Excel dll Version 11 and will be overwrite by the XlSaveConflictResolution.

The code is fairly straight forward, the please refer to my old post on how i clean up the resources before quit.

c# detect excel install location in registry and open file

public void OpenInExcel(string filename)
        {
            string dir = "";
            RegistryKey key = Registry.LocalMachine;
            RegistryKey excelKey = key.OpenSubKey(@"SOFTWARE\MicroSoft\Office");
            if (excelKey != null)
            {
                foreach (string valuename in excelKey.GetSubKeyNames())
                {
                    int version = 9;
                    double currentVersion=0;
                    if (Double.TryParse(valuename, out currentVersion) && currentVersion >= version)
                    {
                        RegistryKey rootdir = excelKey.OpenSubKey(currentVersion + @".0\Excel\InstallRoot");
                        if (rootdir != null)
                        {
                            dir = rootdir.GetValue(rootdir.GetValueNames()[0]).ToString();
                            break;
                        }
                    }
                }                
            }
            if (dir != "")
            {
                ProcessStartInfo startInfo = new ProcessStartInfo();

                startInfo.FileName = dir + @"Excel.exe";
                startInfo.Arguments = "\"" + fileName + "\"";
                startInfo.UseShellExecute = false;

                using (Process process = new Process())
                {
                    process.StartInfo = startInfo;
                    try
                    {
                        process.Start();
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine("\n\nCould not start Excel process.");
                        Console.WriteLine(ex);
                    }
                }
            }
            else
            {
                MessageBox.Show("Can't Open in excel because excel is not installed.");
            }
        }     

c# revert a LinkedList

void ReverseLinkedList(LinkedList ls)
{
    if ( ls == null || ls.Head == null )
        return;
    ListNode head = ls.Head;
    ListNode current = head.Next;
    while(current!=null)
    {
        ListNode tmp = current;
        current = current.Next;
        tmp.Next = head;
        head = tmp;
    }
    ls.Head.Next = null;
    ls.Head = head;
}

c# merge sort algorithm implementation

        private int[] MergeSort(int[] a)
        {
            if ( a.Length == 1)
                return a;
            int middle = a.Length / 2;
            int[] left = new int[middle];
            for (int i = 0 ; i < middle ; i ++)
            {
                left[ i ] = a[ i ];
            }
            int[] right = new int[a.Length - middle];
            for( int i = 0; i < a.Length - middle; i++ )
            {
                right[i] = a[i+middle];
            }
            left = MergeSort( left );
            right = MergeSort( right );

            int leftptr = 0;
            int rightptr = 0;

            int[] sorted = new int[a.Length];
            for(int k = 0 ; k < a.Length; k++)
            {
                if ( rightptr == right.Length || ((leftptr < left.Length ) && (left[leftptr] <= right[rightptr])))
                {
                    sorted[ k ] = left[ leftptr ];
                    leftptr++;
                }
                else if( leftptr == left.Length || ((rightptr < right.Length ) && (right[rightptr] <= left[leftptr] )))
                {
                    sorted[k] = right[rightptr];
                    rightptr++;
                }
            }
            return sorted;            
        }

c# Quick Sort Algorithm Implementation

private void QuickSort( int[] a, int left, int right ) 
        { 
            if( a == null ) 
                return; 
            int i = left; 
            int j = right; 
            int pivot = a[( left + right ) / 2]; 
            while( i <= j ) 
            { 
                while( a[i] < pivot ) 
                    i++; 
                while( a[j] > pivot ) 
                    j--; 
                if( i <= j ) 
                { 
                    int tmp = a[i]; 
                    a[i++] = a[j]; 
                    a[j--] = tmp; 
                } 
            } 
            if( j > left ) 
            { 
                QuickSort( a, left, j ); 
            } 
            if( i < right ) 
            { 
                QuickSort( a, i, right ); 
            } 
        }

c# insert sort algorithm implementation

        private void insert_sort( int[] s )
        {
            for( int k = 1; k < s.Length ; k++ )
            {
                int value = s[k];
                for( int i = 0; i <= k - 1; i++ )
                {
                    if( value < s[i] )
                    {
                        for( int j = k - 1; j >= i; j-- )
                            s[j + 1] = s[j];
                        s[i] = value;
                        break;
                    }
                }
            }
        }