Welcome!

Microsoft Cloud Authors: Yeshim Deniz, Janakiram MSV, John Katrick, David H Deans, Andreas Grabner

Related Topics: Microsoft Cloud

Microsoft Cloud: Article

.NET Gotchas

Using a technology well

You might be wondering what this book is all about. As the author explains, the dictionary's definition of a gotcha is "an unexpected usually disconcerting challenge, revelation, or catch". Mr. Subramaniam defines the gotchas in his book as "those things that pop up unexpectedly when you're programming in .NET. … In this book I focus on the .NET framework and features that have consistently exhibited behavior that was not obvious to me." Mr. Subramaniam explains that the purpose of his book is not just to explain how to use a technology "but how to use it well and do things right". The book is intended for ".NET programmers in the trenches". He assumes that you are fairly familiar with .NET and all gotchas are presented in C# and VB.NET. The book is organized into 8 chapters focusing in on different areas of interest. Each topic in a chapter includes a discussion of the gotcha, code examples and possible solutions. There are also footnotes and a bibliography for further study of the topic.

The book contains fascinating discussions on a myriad of topics. Some of the topics discussed are Language API Gotchas, Visual Studio and Complier Gotchas as well as Inheritance and Polymorphism Gotchas If you do a lot of multithreading you will definitely want to read this chapter.

I would like to present a Gotcha that I have encountered that Mr. Subramaniam touches on in Gotcha #2: struct and classdiffer in behavior" and is discussed by Les Smith in his article located at www.knowdotnet.com/articles/boxedstructures.html. In .NET a class is treated as a reference type while a structure is treated as a value type. The gotcha occurs when you place a structure inside an arraylist. If you try to iterate through the arraylist to make changes to each structure, you will be surprised to find that the changes do not take effect. In my code below, I declare a structure and an arraylist. I add two entries to the arraylist and then iterate through the list to change the value of gamesPlayed.

Option Strict On

Public Structure Player
      Public firstName As String
      Public lastName As String
      Public gamesPlayed As Integer
End Structure

Public Sub ArrayList_Structure

    Dim myTeam As New ArrayList
    Dim myPlayer As Player
    Dim intCount As Integer
    Dim intEnd As Integer

    myPlayer.firstName = "Bob"
    myPlayer.lastName = "Smith"
    myPlayer.gamesPlayed = 0
    myTeam.Add(myPlayer)

    myPlayer.firstName = "Jane"
    myPlayer.lastName = "Doe"
    myPlayer.gamesPlayed = 0
    myTeam.Add(myPlayer)

    For Each myPlayer In myTeam

      myPlayer.gamesPlayed += 1

Next

   For Each myPlayer In myTeam

      Response.Write( _
        myPlayer.firstName _& " " _
        & myPlayer.lastName _& " " _
        & myPlayer.gamesPlayed.ToString _
          & "<br/>")

Next

The results of this code are:

Bob Smith 0
Jane Doe 0

This is definitely not what you expected but is due to the fact that structures and arraylist are different types. To solve this problem you could do the following:

intCount = 0
intEnd = myTeam.Count - 1

While intCount <= intEnd

    myPlayer = CType(myTeam(intCount), Player)
    myPlayer.gamesPlayed += 1
    myTeam(intCount) = myPlayer
    intCount += 1

End While

For Each myPlayer In myTeam

Response.Write( _
    myPlayer.firstName _& " " _
    & myPlayer.lastName _& " " _
    & myPlayer.gamesPlayed.ToString _
    & "<br/>")

Next

End Sub

By converting the selected entry back into a structure you are now able to change it and then you can put it back into the arraylist with the following results.

Bob Smith 1
Jane Doe 1

.Net Gotchas is a very interesting book that covers a whole slew of topics. It is well worth reading especially if you have encountered the same gotchas and could not discover a way to solve them.

More Stories By Steven Mandel

Steven Mandel has worked in the IT industry for over 15 years designing databases using Microsoft Access and SQL Server. He has developed Web and Windows applications using VB.NET and has written numerous articles and reviews about ASP.NET and VB.NET.

Comments (4) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
Nmixer 01/24/08 07:15:51 PM EST

Thank you for that, I was not sure exactly how an arraylist works and did not realize it can hold an array of objects like a structure. and reading your example made me relies that i could :) so thanks.
this is what i searched to get this page "declaring a structure as an arraylist" odd isn't it?

anyways thanks

Jackson123r 06/26/07 04:50:34 AM EDT

I love the new iphone because it has cool things that it never has before in its daily life a wireless internet connection modulator

www.iphone-converter.org/convert-iphone/

.NET News Desk 05/10/06 04:31:53 PM EDT

You might be wondering what this book is all about. As the author explains, the dictionary's definition of a gotcha is 'an unexpected usually disconcerting challenge, revelation, or catch'. Mr. Subramaniam defines the gotchas in his book as 'those things that pop up unexpectedly when you're programming in .NET. ? In this book I focus on the .NET framework and features that have consistently exhibited behavior that was not obvious to me.' Mr. Subramaniam explains that the purpose of his book is not just to explain how to use a technology 'but how to use it well and do things right'. The book is intended for '.NET programmers in the trenches'. He assumes that you are fairly familiar with .NET and all gotchas are presented in C# and VB.NET.

Matt J. 05/04/06 01:52:48 PM EDT

Having not seen the list of gotchas discussed, here's a simple one that got me: In VB, even though I set the default to Compare Text, functions like String.IndexOf() are still case sensitive! I understand why. I just don't like it!

@ThingsExpo Stories
DX World EXPO, LLC, a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
"Space Monkey by Vivent Smart Home is a product that is a distributed cloud-based edge storage network. Vivent Smart Home, our parent company, is a smart home provider that places a lot of hard drives across homes in North America," explained JT Olds, Director of Engineering, and Brandon Crowfeather, Product Manager, at Vivint Smart Home, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that Conference Guru has been named “Media Sponsor” of the 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. A valuable conference experience generates new contacts, sales leads, potential strategic partners and potential investors; helps gather competitive intelligence and even provides inspiration for new products and services. Conference Guru works with conference organizers to pass great deals to gre...
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develop...
In his Opening Keynote at 21st Cloud Expo, John Considine, General Manager of IBM Cloud Infrastructure, led attendees through the exciting evolution of the cloud. He looked at this major disruption from the perspective of technology, business models, and what this means for enterprises of all sizes. John Considine is General Manager of Cloud Infrastructure Services at IBM. In that role he is responsible for leading IBM’s public cloud infrastructure including strategy, development, and offering m...
"Evatronix provides design services to companies that need to integrate the IoT technology in their products but they don't necessarily have the expertise, knowledge and design team to do so," explained Adam Morawiec, VP of Business Development at Evatronix, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
To get the most out of their data, successful companies are not focusing on queries and data lakes, they are actively integrating analytics into their operations with a data-first application development approach. Real-time adjustments to improve revenues, reduce costs, or mitigate risk rely on applications that minimize latency on a variety of data sources. In his session at @BigDataExpo, Jack Norris, Senior Vice President, Data and Applications at MapR Technologies, reviewed best practices to ...
Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
Large industrial manufacturing organizations are adopting the agile principles of cloud software companies. The industrial manufacturing development process has not scaled over time. Now that design CAD teams are geographically distributed, centralizing their work is key. With large multi-gigabyte projects, outdated tools have stifled industrial team agility, time-to-market milestones, and impacted P&L stakeholders.
"Akvelon is a software development company and we also provide consultancy services to folks who are looking to scale or accelerate their engineering roadmaps," explained Jeremiah Mothersell, Marketing Manager at Akvelon, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
In his session at 21st Cloud Expo, Carl J. Levine, Senior Technical Evangelist for NS1, will objectively discuss how DNS is used to solve Digital Transformation challenges in large SaaS applications, CDNs, AdTech platforms, and other demanding use cases. Carl J. Levine is the Senior Technical Evangelist for NS1. A veteran of the Internet Infrastructure space, he has over a decade of experience with startups, networking protocols and Internet infrastructure, combined with the unique ability to it...
22nd International Cloud Expo, taking place June 5-7, 2018, at the Javits Center in New York City, NY, and co-located with the 1st DXWorld Expo will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud ...
"Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
Gemini is Yahoo’s native and search advertising platform. To ensure the quality of a complex distributed system that spans multiple products and components and across various desktop websites and mobile app and web experiences – both Yahoo owned and operated and third-party syndication (supply), with complex interaction with more than a billion users and numerous advertisers globally (demand) – it becomes imperative to automate a set of end-to-end tests 24x7 to detect bugs and regression. In th...
"MobiDev is a software development company and we do complex, custom software development for everybody from entrepreneurs to large enterprises," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
"There's plenty of bandwidth out there but it's never in the right place. So what Cedexis does is uses data to work out the best pathways to get data from the origin to the person who wants to get it," explained Simon Jones, Evangelist and Head of Marketing at Cedexis, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.