Is there an official C# guideline for the order of items in terms of class structure?
Does it go:
I'm curious if there is a hard and fast rule about the order of items? I'm kind of all over the place. I want to stick with a particular standard so I can do it everywhere.
The real problem is my more complex properties end up looking a lot like methods and they feel out of place at the top before the constructor.
Any tips/suggestions?
According to the StyleCop Rules Documentation the ordering is as follows.
Within a class, struct or interface: (SA1201 and SA1203)
Within each of these groups order by access: (SA1202)
Within each of the access groups, order by static, then non-static: (SA1204)
Within each of the static/non-static groups of fields, order by readonly, then non-readonly : (SA1214 and SA1215)
An unrolled list is 130 lines long, so I won't unroll it here. The methods part unrolled is:
The documentation notes that if the prescribed order isn't suitable - say, multiple interfaces are being implemented, and the interface methods and properties should be grouped together - then use a partial class to group the related methods and properties together.
public static fields, etc - i.e. does one go by field name or by type then field name? (e.g. public int a; public bool b; or public bool b; public int a;? –
Theresiatheresina internal above protected internal when former is the more restrictive scope? There is no logical order for this whatsoever. I raised this in one of the relevant github issues and the answer I got was: "meh, it was how some guy decided to do back in the day". –
Robot Rather than grouping by visibility or by type of item (field, property, method, etc.), how about grouping by functionality?
This is an old but still very relevant question, so I'll add this: What's the first thing you look for when you open up a class file that you may or may not have read before? Fields? Properties? I've realized from experience that almost invariably I go hunting for the constructors, because the most basic thing to understand is how this object is constructed.
Therefore, I've started putting constructors first in class files, and the result has been psychologically very positive. The standard recommendation of putting constructors after a bunch of other things feels dissonant.
The upcoming primary constructor feature in C# 6 provides evidence that the natural place for a constructor is at the very top of a class - in fact primary constructors are specified even before the open brace.
It's funny how much of a difference a reordering like this makes. It reminds me of how using statements used to be ordered - with the System namespaces first. Visual Studio's "Organize Usings" command used this order. Now usings are just ordered alphabetically, with no special treatment given to System namespaces. The result just feels simpler and cleaner.
I don't know about a language or industry standard, but I tend to put things in this order with each section wrapped in a #region:
using Statements
Namespace
Class
Private members
Public properties
Constructors
Public methods
Private methods
I would recommend using the coding standards from IDesign (webarchive) or the ones listed on Brad Abram's website. Those are the best two that I have found.
Brad would say...
Classes member should be alphabetized, and grouped into sections (Fields, Constructors, Properties, Events, Methods, Private interface implementations, Nested types)
My preference is to order by kind and then be decreasing visibility as follows
public methods
public events
public properties
protected methods
protected events
protected properties
private methods
private events
private properties
private fields
public delegates
public interfaces
public classes
public structs
public records
protected delegates
protected interfaces
protected classes
protected structs
protected records
private delegates
private interfaces
private classes
private structs
private records
I know this violates Style Cop and if someone can give me a good reason why I should place the implementation details of a type before its interface I am willing to change. At present, I have a strong preference for putting private members last.
Note: I don't use public or protected fields.
As mentioned before there is nothing in the C# language that dictates the layout, I personally use regions, and I do something like this for an average class.
public class myClass
{
#region Private Members
#endregion
#region Public Properties
#endregion
#region Constructors
#endregion
#region Public Methods
#endregion
}
It makes sense to me anyway
Usually I try to follow the next pattern:
Each part (static and instance) consists of the following member types:
Then the members are sorted by visibility (from less to more visible):
The order is not a dogma: simple classes are easier to read, however, more complex classes need context-specific grouping.
From StyleCop
private fields, public fields, constructors, properties, public methods, private methods
As StyleCop is part of the MS build process you could view that as a de facto standard
The closest you're likely to find is "Design Guidelines, Managed code and the .NET Framework" (http://blogs.msdn.com/brada/articles/361363.aspx) by Brad Abrams
Many standards are outlined here. The relevant section is 2.8 I think.
I prefer to put the private fields up at the top along with the constructor(s), then put the public interface bits after that, then the private interface bits.
Also, if your class definition is long enough for the ordering of items to matter much, that's probably a code smell indicating your class is too bulky and complex and you should refactor.
I keep it as simple as possible (for me at least)
Enumerations
Declarations
Constructors
Overrides
Methods
Properties
Event Handler
I know this is old but my order is as follows:
in order of public, protected, private, internal, abstract
I also like to write out properties like this (instead of the shorthand approach)
// Some where in the fields section
private int someVariable;
// I also refrain from
// declaring variables outside of the constructor
// and some where in the properties section I do
public int SomeVariable
{
get { return someVariable; }
set { someVariable = value; }
}
the only coding guidelines I've seen suggested for this is to put fields at the top of the class definition.
i tend to put constructors next.
my general comment would be that you should stick to one class per file and if the class is big enough that the organization of properties versus methods is a big concern, how big is the class and should you be refactoring it anyway? does it represent multiple concerns?
I have restructured the accepted answer, as to what I think is a better layout:
Within a class, struct or interface:
Within each of these groups order by access:
Within each of the access groups, order by static, then non-static:
I also feel that nested types should be kept to a minimum. All to often I see people having nested classes, enums, delegates that would be better of being a separate instance. There hardly ever is any gain of making a type nested. Put them in separate files as well. A file with 5 classes feels cluttered to me.
There certainly is nothing in the language that enforces it in any way. I tend to group things by visibility (public, then protected, then private) and use #regions to group related things functionally, regardless of whether it is a property, method, or whatever. Construction methods (whether actual ctors or static factory functions) are usually right at the top since they are the first thing clients need to know about.
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publicandprotectedmembers. – Robotprivateorinternalmembers (I believe). Nice way of seeingpublicandprotected, however. We can see the source of .NET Framework classes, here referencesource.microsoft.com too – Nightingale