C# : scope your global state changes with IDisposable and the using statement


Sometimes we need to modify some global state, but when we do that it’s critical to ensure we leave things as we’ve found them; you know like when you lift the toilet seat: forgetting to put it down afterwards could get you in trouble!
It’s similar in programming and you need to use the right tools and practices.

If you regularly work with C# it’s very likely you’ve already used the IDisposable interface along with the using statement, two tools that help you scope the use of a resource.

In this article I’ll show you how they can be used to scope global state changes in a fluent manner, a pattern I’ve used for years to enhance reusability and readability of this kind of code.
In the first part I’ll illustrate this pattern with a small and hopefully fun example, and then in the second part I’ll describe how it can be applied to other situations like culture settings and Excel development.
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“If all you have is a hammer…

…everything looks like a nail” says the proverb.

I’ll illustrate it with a little story about a common mistake I see sometimes.

(Code samples are in C# but use only basic features so C++ and Java developers should not be too disoriented.)

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Extend your VBA code with C#, VB.Net or C++/CLI


If you have an important VBA code base you know how difficult it is to maintain it, not because VBA is inherently a bad or poor platform but because the developers are often either end-users not aware of good development practices or professional developers not skilled enough in VBA development who have learnt it on the job. In both cases, more often than not, you end up with poor quality source code.

There is other forces that make VBA development less appealing, as the pressure of software vendors like Microsoft who’d like to sell you not just Office but Office+Visual Studio and then promotes other technologies like .Net with languages such as C# and VB.Net. Just have a look at the evolution of the VBA editor design and capabilities since 10 years and you’ll understand that it does not benefit from fanatic development and promotion efforts.

It’s why you should avoid the headlong rush and restrict your VBA development efforts to the bare minimum: for new developments you should consider other languages and platforms like C# and VB.Net with the .Net framework as they seamlessly integrate with the Office suite, with little overhead compared to the direct integration of VBA, and give you access to a wealth of modern technologies.
But don’t be fooled by the FUD about the dangers of keeping a legacy VBA code base and do your due diligence: does the guy who suggest you a full migration will do it for free or is he paid for the job? ;) A full migration may be a necessity: not because the platform is VBA but because the application is buggy, undocumented, out of control and using it creates a true operational risk, and this is true for any application and technology including the newest.

Then, if you have a VBA application that is working perfectly, is documented and controlled, an alternative to both the headlong rush and the full migration is the integration of .Net components with VBA, you then use a future-proof technology to develop new features and/or replace legacy features as you go along, avoiding the big-bang effect.

So now you know what to do and right now I’ll show you how to do this seamless transition from VBA to greener pastures by implementing a simple API with three popular .Net languages: C# (the king), VB.Net (the prince) and C++/CLI (the Jack of all trades, master of none).

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Essential tools for debugging and troubleshooting : Dependency Walker aka Depends


This is the first article of the “Essential tools for debugging and troubleshooting” series.
Visit the series main page for more information and to discover other tools.

Dependency Walker

Dependency walker (a.k.a Depends) is a simple yet powerful tool that you’ll find invaluable if you have to track the native dependencies of your components (EXE or DLL).
Dependency Walker can be used for static (without having to run any code) or dynamic analysis (with dependencies tracked while running your code).

I’ll illustrate its usefulness with a from scratch sample.
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