Beware of too concise code

Introduction

As developers we often strive to build concise code in order to avoid useless ceremony that would distract from its purpose.

We do that by leveraging the syntactic sugar offered by the languages to reduce code verbosity and increase its expressiveness but it can become a trap and lead to code that does not do what is expected.

In this article, I’ll illustrate this point with a powerful C# feature: async methods.

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When semicolons matter

Introduction

Younger I was a dogmatic developer blindly enforcing the IT gurus’ dogma, later I’ve become more pragmatic preferring code readability and maintainability.
In JavaScript, it means omitting the semicolons to lighten the code and remove useless ceremony.

But in some rare corner cases omitting a semicolon can completely change the way the compiler interprets the code.
Hopefully, it will cause a compilation error, and in the worst case a hidden bug hard to track.

In this article, I describe one of these corner cases.

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A basic use-case for Task Unwrap

Introduction

Recently, after months without using .Net/C#, I was enhancing an existing .Net/C# WPF application leveraging the .Net Task Parallel Library (TPL).

But naively applying the JavaScript Promises patterns I had used in the previous months I was bitten by a strange issue which forced me to use the quite exotic Unwrap extension method.

This article describes the issue, explains its cause, provides a fix with Unwrap, and finally provides a more modern version with the C# 5.0 async/await paradigm.

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Optional passed by reference parameters with C# for VBA COM APIs

Introduction

If you’ve already developed COM APIs with .Net, typically in C# with VBA as the consuming language, you’ve probably leveraged two powerful features:

  • by-reference parameter passing that allows the API to change the input object itself, not only its content.
    This is marked with ref in C#:

    void LoadData(ref string data)
  • optional parameters that allow the caller to omit them when calling into the API:
    void SaveData(string data = "DEFAULT")

Sometimes you want to have both for a parameter: the ability to omit it and to change it.
This is something COM supports but unfortunately this is not supported by C#.
Recently one of my customer needed precisely that for a COM API developed in C# migrated from VB6 where it was plug-and-play.
The original developers of the API had done a quick study and concluded that it was not possible with the new C# API and indeed it was not documented at all.
From experience I know that COM is not used a lot today and that resources are scarce, so, to be sure, I’ve done my due diligence and reexamined the issue, digging a little deeper and testing undocumented stuff.
I’ve finally found a solution that I would describe as a “trick”, because it’s not documented, and that I’ll present in detail in this article.
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[FRENCH] Est-ce la fin de WPF: présent et futur de WPF

Introduction

En tant que développeur et formateur WPF depuis plusieurs années les nouvelles orientations de Microsoft pour les plateformes clientes, avec la montée en puissance du tout nouveau WinRT, m’ont quelque peu inquiétées.

Et pour cause : j’ai directement subi l’échec et l’abandon de Silverlight et comme dit le proverbe “chat échaudé craint l’eau froide”.
Depuis 2009 j’ai beaucoup investi, personnellement et professionnellement, dans WPF, l’utilisant pour développer des applications LOB dans le secteur financier, et désormais je dispense même des formations sur le sujet.
Par conséquent le futur de WPF est critique pour moi, c’est pourquoi j’ai étudié cette question de l’avenir de WPF plus en détails, mettant en oeuvre mon expertise sur le sujet et ma récente découverte de WinRT.

Dans cet article je partagerai avec vous les résultats de cette “étude” en toute objectivité et transparence, afin de vous aider en tant que partie prenante dans votre veille technologique.
J’espère que vous fournirez vos propres informations, afin que la communauté toute entière puisse avoir une meilleure vision des perspectives pour WPF.
Dans la dernière partie de l’article je fournis des stratégies pour les entreprises et les développeurs utilisant WPF.

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Is WPF dead: the present and future of WPF

Introduction

As a WPF developer for years I was recently concerned by the new direction chosen by Microsoft on its client platforms with the rise of the brand new WinRT framework.

I was concerned for good reasons: I’ve suffered from the collateral damages of the Silverlight failure, and as the proverb says “once bitten, twice shy”.
Since 2009 I have put a huge personal and professional investment in WPF, using it to develop LOB applications in the financial industry, and now I’m even providing training on this topic.
So as a professional developer and trainer the future of WPF is critical for me so I’ve studied this issue more thoroughly.

In this article I’ll share my findings with you, in a completely objective and transparent manner, and I hope you’ll provide your own facts, so that the community can have a better vision of the future of WPF.
In the last part of this article I provide some strategies for businesses and individual developers.

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Book review : “MCSD Certification Toolkit (Exam 70-483): Programming in C#”

Introduction

I’ve recently passed the Microsoft 70-483 “Programming in C#” certification which is one of the entry point into the .Net and WinRT developers certification cycles.
To be well prepared I’ve read the two books entirely dedicated to this certification : MCSD Certification Toolkit (Exam 70-483): Programming in C# and Exam Ref 70-483: Programming in C#.
I strongly recommend you read both of them if you intend to pass the certification.
Indeed both have been my main material to prepare for the certification and they have perfectly done the job.

This article is a complete review of MCSD Certification Toolkit (Exam 70-483): Programming in C#.
This is the first book you should read because I think this is the one that will best prepare you to get the certification, but paradoxically the worst from a technical point of view, and you will quickly understand why.

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[FRENCH] Revue du livre “MCSD Certification Toolkit (Exam 70-483): Programming in C#”

Book cover

Introduction

J’ai tout récemment passé et obtenu la certification Microsoft 70-483 “Programming in C#” qui est l’un des points d’entrée des cycles de certification développeur .Net et WinRT.
Pour m’y préparer j’ai notamment lu les 2 livres qui y sont dédiés (en anglais) : MCSD Certification Toolkit (Exam 70-483): Programming in C# et Programming in C#: Exam Ref 70-483 dont je vous conseille vivement la lecture.
Ils ont en effet constitué mon support principal pour la préparation de la certification et ont bien remplis leur office.

Cet article est une revue complète de MCSD Certification Toolkit (Exam 70-483): Programming in C#.
C’est le 1er livre que vous devriez lire, je pense celui qui prépare le mieux à la certification, mais paradoxalement le moins bon techniquement, et vous allez vite comprendre pourquoi.

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Leverage the .Net framework classes from VBA

Introduction

Following my previous article on a similar subject, Extend your VBA code with C#, VB.Net or C++/CLI, I’ve received an interesting feedback from a VBA developer who wanted to leverage the advanced support of the .Net framework for regular expressions.

This is clearly another interesting use-case for Excel addins and in this article I’ll quickly demonstrate how to build a wrapper which will close the gap between your VBA code and the .Net framework.

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Relative performance of ReaderWriterLockSlim

Introduction

I’ve recently wanted to demonstrate the relevance of the .Net ReaderWriterLock[Slim] synchronization primitives.
It’s good to hear from the vendor that it’s better, faster, stronger, but when you can it’s always good to evaluate it yourself; not that I don’t trust vendors, but because I like to have hard numbers, particularly when I assert something that can be critical for my participants’ developments.

So I’ve built a small, simple and I hope relevant benchmark to measure the performance impact of ReaderWriterLock[Slim] compared to the naive and uniform use of a Monitor using the C# lock construct.

I wanted to check these two things:

  • that the RW locks behave as advertised,
  • what is the profile of the gain function.

In this article I’ll explain the rationales behind the benchmark, how I’ve implemented it and finally present the results.

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