Are .NET Properties a Mistake?

Are .NET Properties a Mistake?

As I mentioned the other day, I'm reading Jeffrey Richter's book CLR via C# right now. I was kind of surprised to read this statement by the author: "If I had been involved in the design of the .NET Framework and compilers, I would not have offered properties at all..." (p. 218)

Mr. Richter's reason for disliking properties is that they look like fields but don't behave like them, thus confusing developers. He gives a good list of ways in which properties are different from fields -- think of all the ways that a zero argument method is different from a field and you'll about have it -- saying that those differences are bound to trip people up.

I disagree for a couple of reasons:

  1. Properties are really pretty easy to grasp.
  2. Most programmers adhere to the rule that all fields are private (which Mr. Richter also recommended), so there aren't really fields to be confused by. Expect everything to be a method and you'll generally be fine.

I say "generally" because there are some cases where the opposite is true: a property can behave more like a field than a method. For example, you can use the postfix increment operator on a property (that has both get and set accessors) and it behaves as it would on a field. That is, the operator gets the property value and sets the incremented value back in. [Added June 26, 2008]

A benefit of properties that isn't really mentioned in the book is a more explicit (for lack of a better word) "bean-ness". Java has the bean concept, where an object has get and set methods to create a set of properties, but the C# syntax is more elegant and apparent. With the explicit properties, you can do things like XML serialization, property editors, etc. with reasonable default behavior.

It's probably true that .NET properties get abused and overused (see the official guidelines), but I still kind of like them.