Covariance Revisited 

Covariance is really important in .NET library collections, but here's an example of where it can be useful in application code.
Source code available at: github.com/JasperKent/Covaria...
Topics include:
- WPF graphics
- Testing WPF with xUnit using [StaFact]
- Generic base classes
- Generic interfaces
- Avoiding downcasting
- Implementing covariance in C# with 'out'

Наука