I’m a big believer in Test Driven Development as an effective practice that helps me write high quality, maintainable code. TDD is a practice I not only apply on larger enterprise applications, but something I try to do even on smaller mobile apps. In the day of the Apple App Store or Microsoft Marketplace you are relying on Apple or Microsoft to approve your application before it’s made available to your users. The process typically takes around a week – meaning it can potentially take a week before you fix a bug and the update is made available to the users. Introducing a bug in your mobile app can greatly hurt your rating in the Marketplace/App Store. Given the fact that you cannot simply upload a quick fix to the app stores, like you can on a web application, having solid testing for mobile applications is even more important than for other types of applications.

With this in mind I was thrilled to see that Microsoft Pattern & Practices had taken this to hearth in their latest guidance for building Windows Phone 7 applications. The latest guide includes three major topics:

One of the big new features of Windows Phone 7.5 (code named Mango) is direct camera access. Having access to the camera stream enables several new scenarios, such as in-app QR and barcode scanning, augmented reality applications or custom looking photo camera UI. There are some good resources on how to use the new APIs to access the camera in Mango, but I haven’t found any complete examples of how to implement a QR code scanner, which is what I am going to do in this blog post.

Earlier this summer I gave a presentation at NDC 2011 about writing cross platform mobile applications using C# and .NET. At the time of the presentation the future of MonoTouch and Mono for Android was uncertain, but with the recent news of Xamarin gaining ownership of the products, the future of C# on iOS and Android looks brighter than ever.