Why prefix C# interface names with an “I”

Question

What is the rationale behind this naming convention?

I don\'t see any benefit. The extra prefix just pollutes the API.

My thinking is inline with Konrad\'s respo

Answer 1

Why isn't this a function of syntactical highlighting instead of Hungarian notation? Why doesn't the IDE just italicize identifiers that refer to interfaces if it's so important to distinguish between classes and interfaces. I hate putting "" or "m" before fields, "C" before classes, etc. Even worse, it encourages programmers write really bad APIs such as:

public class List : IList

instead of a more reasonable:

public class LinkedList : List
public class ArrayList : List
public class HashList : List

Even the .NET common class authors fell into this trap. A class name should NEVER be the name of the interface with just the "I" removed. The class name should always tell the user how the class differs from other possible implementations of the interface(s). I vote for dropping the stupid "I" for that reason alone.

Also, when I use intellisense, I want to group things by functional area, not whether it's a class or interface. I never think, "I need an interface, not a class." I always think, "I need something that does X".