An introduction to Inversion of Control, using the Dependency Injection and Service Locator patterns, along with simple examples in C#.
Lately I’ve had my eyes opened to a few great tools for .NET development that I haven’t used before.
While it’s a very old feature in Visual Studio it was news to me that you could select columns of text.
Simplify conditional code using the "delegate dictionary" pattern.
Out of the five SOLID principles the Open/Closed Principle is probably the one that I’ve had the hardest time understanding. However, a while ago though I found some code that I had written years ago that made me think to myself “Hey, this is clearly violating the Open Closed Principle!”.