December Update of the Coding Guidelines for C# 3.0 and C# 4.0

I finally found some time to update the coding guidelines with some feedback I received since it’s original release in June this year. I’ve removed the following guidelines because I found that they were either very exotic or not general enough for most developers:

• Avoid side-effects when throwing recoverable exceptions (AV1044)
• Don’t make assumptions on the object’s state after raising an event (AV1050)
• Adhere to the LINQ Design Guidelines for custom IQueryable implementations (AV1075)
• Explicitly define the scope of a type or member (AV1551) because it is a duplicate of AV1501.

I also noticed that the Design Guidelines section is getting bigger with each new version, so I split up that section into three smaller sections. And because of that, I had to renumber the guidelines in the AV1025-1100 range as well. So what about the new guidelines?

Well, these are new ones:

• Use an interface to support multiple implementations, not a base class (AV1004)

• Use an interface to decouple classes from each other (AV1005)

• Avoid bidirectional dependencies (AV1020)

• Classes should have state and behavior (AV1025)

• Avoid mutual exclusive properties (AV1110)
• Don’t expose stateful objects through static members (AV1125)
• Use exceptions instead of return codes for reporting failures (AV1200)
• Don’t use nested loops in a method (AV1532)

• Consider abstracting an external dependency or 3rd party component (AV1580)

As usual, you can download the latest version, its A4 cheat sheet, and Visual Studio 2010 rule sets at www.csharpcodingguidelines.com.