Using interfaces when you aren’t going to have multiple implementations of it is an example of interface overuse. Creating an interface for a class that matches the public members of the class ...

Until C# 8.0, an interface in C# could not contain method definitions. You could only include method declarations in an interface, and the members of an interface were public and abstract by default.

Default interface methods are included in a new feature proposal for C# 8, which will allow developers to use the traits programming technique on the .NET platform.

Checking If You Can Use a Class in C# The is keyword lets you check if a variable is pointing to an object of a particular class (or a class that inherits from some class). For example, the code in ...

A contravariant type may be substituted by one of its base classes. Prior to .NET 4.5, the primary covariant collection interface was IEnumerable<out T>. If you wanted to have a read-only view of a ...