Skip to main content

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

5
  • The I stands for...ready..."Interface" Commented Mar 18, 2009 at 21:02
  • 1
    Yes, and that is quite obvious. The real question is, why would anyone care if they're using interfaces, abstract classes or concrete classes? Does it matter to you if you accept an ICustomerService or a CCustomerService in the CTOR of your object? Commented Mar 19, 2009 at 6:56
  • It's just convention. Makes it easy to find the interface as well. I have tried removing it and I didn't really like it as some concrete classes were named the same ICustomerService and CustomerService, if you drop the I then they are the same. I don't want to have to think about naming it more cleverly, I just want to move on with the code. Commented Nov 20, 2009 at 23:51
  • For the reason behind the I-prefix, see (for example) Interface naming convention on StackOverflow: which quotes Brad Abrams: "...the 'I' prefix on interfaces is a clear recognition of the influence of COM (and Java) on the .NET Framework" Commented Jan 21, 2015 at 15:35
  • @Magnus "Does it matter to you if you accept an ICustomerService or a CCustomerService in the CTOR of your object?" Absolutely it does! In OOP you should "program to an interface, not an implementation." The "I" prefix easily lets you distinguish between interfaces and implementations, so you can ensure you're not accidentally specifying concrete parameters in your class constructors. Commented Aug 9, 2017 at 13:42