Welcome!

Microsoft Cloud Authors: Nick Basinger, Kevin Benedict, Pat Romanski, Liz McMillan, Lori MacVittie

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)

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.


IoT & Smart Cities Stories
This month @nodexl announced that ServerlessSUMMIT & DevOpsSUMMIT own the world's top three most influential Kubernetes domains which are more influential than LinkedIn, Twitter, YouTube, Medium, Infoworld and Microsoft combined. NodeXL is a template for Microsoft® Excel® (2007, 2010, 2013 and 2016) on Windows (XP, Vista, 7, 8, 10) that lets you enter a network edge list into a workbook, click a button, see a network graph, and get a detailed summary report, all in the familiar environment of...
At CloudEXPO Silicon Valley, June 24-26, 2019, Digital Transformation (DX) is a major focus with expanded DevOpsSUMMIT and FinTechEXPO programs within the DXWorldEXPO agenda. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of business. Only 12% still survive. Similar percentages are found throug...
IT professionals are also embracing the reality of Serverless architectures, which are critical to developing and operating real-time applications and services. Serverless is particularly important as enterprises of all sizes develop and deploy Internet of Things (IoT) initiatives. Serverless and Kubernetes are great examples of continuous, rapid pace of change in enterprise IT. They also raise a number of critical issues and questions about employee training, development processes, and opera...
AI and machine learning disruption for Enterprises started happening in the areas such as IT operations management (ITOPs) and Cloud management and SaaS apps. In 2019 CIOs will see disruptive solutions for Cloud & Devops, AI/ML driven IT Ops and Cloud Ops. Customers want AI-driven multi-cloud operations for monitoring, detection, prevention of disruptions. Disruptions cause revenue loss, unhappy users, impacts brand reputation etc.
At CloudEXPO Silicon Valley, June 24-26, 2019, Digital Transformation (DX) is a major focus with expanded DevOpsSUMMIT and FinTechEXPO programs within the DXWorldEXPO agenda. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of business. Only 12% still survive. Similar percentages are found throug...
Atmosera delivers modern cloud services that maximize the advantages of cloud-based infrastructures. Offering private, hybrid, and public cloud solutions, Atmosera works closely with customers to engineer, deploy, and operate cloud architectures with advanced services that deliver strategic business outcomes. Atmosera's expertise simplifies the process of cloud transformation and our 20+ years of experience managing complex IT environments provides our customers with the confidence and trust tha...
The Japan External Trade Organization (JETRO) is a non-profit organization that provides business support services to companies expanding to Japan. With the support of JETRO's dedicated staff, clients can incorporate their business; receive visa, immigration, and HR support; find dedicated office space; identify local government subsidies; get tailored market studies; and more.
At CloudEXPO Silicon Valley, June 24-26, 2019, Digital Transformation (DX) is a major focus with expanded DevOpsSUMMIT and FinTechEXPO programs within the DXWorldEXPO agenda. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of business. Only 12% still survive. Similar percentages are found throug...
As you know, enterprise IT conversation over the past year have often centered upon the open-source Kubernetes container orchestration system. In fact, Kubernetes has emerged as the key technology -- and even primary platform -- of cloud migrations for a wide variety of organizations. Kubernetes is critical to forward-looking enterprises that continue to push their IT infrastructures toward maximum functionality, scalability, and flexibility. As they do so, IT professionals are also embr...
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...