Today at Liones I started working on the integration of a payment service provider (PSP) for a web shop implementation. While I was thinking about the architecture I discovered that it is actually very straightforward and that most of the application flow is reusable in different implementations with other PSPs.

Take a look at the UML diagram below; you will notice that there are actually two flows:

• One synchronous, which guides the user trough the payment screen
• One asynchronous, which notifies when the payment state changed (payment is confirmed or canceled)

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Recently I have been working on a Windows Presentation Foundation (WPF) application designed to manage tasks. It is not the first time I developed an application in WPF. However, I was struggling with the same problem I was struggling with before:

The problem: Coupling my views (WPF) to my domain model (C#).

The solution I came up with back then is to make the domain model aware of the need to bind and implement specific functionality like [System.ComponentModel.INotifyPropertyChanged]. By doing this I cluttered my domain model with non domain model code, which made the model difficult to understand and maintain, basically: No Go!

The solution: Model-View-ViewModel pattern

I went out looking for pattern that could help me to eliminate this code cluttering. After doing some research using my favorite search engine I discovered that there was a pattern for this problem: Model – View – ViewModel (MVVM or M-V-VM).
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Yesterday I decided that it was time to buy my own washing machine, finally. It works like a charm , some of you might think that it something trivial to do but for me it was a huge challenge . Anyway, since my friends are here I wont be rude by writing a long post, see you!

In deze post zal ik een vergelijking maken tussen TDD (Test-Driven Development) en het “Just Say Thanks” Patroon. Test-Driven Development is een werkmethode dat toegepast wordt in de software ontwikkeling. Read the rest of this entry »