Development Central

Some very smart people have balked at the idea of prefixing C# interfaces with the letter “I". While I dislike Hungarian notation, I am in favor of IInterfaces.

My main reason is the C# language itself. Consider this code:

public class Employee : Person

Is Person an interface or a class? Proponents of the no-I convention might say that it shouldn’t matter. In C#, though, it does matter. In a single-inheritance language, you only get one base class. Also, if I want to see all of the behavior for Employee, I may want to look at the code for Person as well if it’s a class.

Java has the implements and extends keywords; C# only has the colon (:). In Java you can identify interfaces at a glance; in C# you can’t.

My other reason is that it’s the standard. Microsoft’s conventions say to prefix interface names with the letter I. Most of the C# code I’ve seen does. Deviating from this convention can confuse developers.

I hope we can see eye to I on this.