Is the #region directive really useful in .NET?

Question

After maintaining lots of code littered with #region (in both C# and VB.NET), it seems to me that this construct is just a bunch of "make work" for the programmer. It's work to PUT the dang things into the code, and then they make searching and reading code very annoying.

What are the benefits? Why do coders go to the extra trouble to put this in their code.

Make me a believer!

Answer 1

There are times when your methods HAVE to be long, especially with web development. In those cases (such as when I've got a gridview with a large, complex object bound to it) I've found it useful to use regions:

#region Declaring variables for fields and object properties

#region Getting the fields in scope

#region Getting the properties of the object

#region Setting Fields

These are discrete sections of the method that COULD be broken out, but it would be difficult (I'd have to use variables with larger scope than I like or pass a LOT of variables as 'out'), and it is basic plumbing.

In this case, regions are perfectly acceptable. In others, they are needless.

I will also use regions to group methods into logical groups. I reject partial classes for this purpose, as I tend to have a lot of pages open when I'm debugging, and the fewer partial classes there are in an object (or page, or dialog), the more of them I can have on my tab list (which I limit to one line so I can see more code).

Regions are only a problem when used as a crutch, or when they cover poor code (for instance, if you are nesting regions inside of each other within the same scope, it's a bad sign).

Answer 2

Like any language feature, regions have the potential to be misused and abused but they also have their benefits.

They are great for creating "folding" groups around:

• methods, especially if you have a lot of overloaded methods
• interface implementations
• operator overloads

You can also use it to group properties, public/private methods, events, class-wide variables, etc.

I use regions in my code to help create a consistent structure in my code so I always know where things are at a glance. Yes, it makes things a bit harder during refactoring or adding new functions (especially when autogenerated by Visual Studio) but I feel it's a small price to pay to keep things consistent and structured.

Answer 3

Our Business Objects all have Regions - and we love them.

We have;

• Business Properties and Methods
• Shared Methods
• Constructors
• Authorization
• Data Access
• Events

We have a few others depending on the type of Business Object we are dealing with (Subscriber etc)

For many classes regions just get in the way - but for our standard business objects they save us a ton of time. These Business Objects are code gen'd, so they are very consistent. Can get to where I want to be way faster than the clutter if they aren't, and the consistency makes it easy to find each other's stuff.

Answer 4

Often times, both partials and #regions are used as a crutch for bad design (e.g. class is too big or tries to do too many things).

The best use I've had for #regions so far is the grouping of functionality that is seen in many different classes. For example, value objects that have getters, setters, constructors and supporting fields. I might very well group those ideas into regions. Its a matter of opinion, however, as to whether that makes code cleaner or harder to read.

Answer 5

I don't generally use code regions, except in one specific case - dependency properties. Although dependecy properties are a pleasure to work with in most respects, their declaraions are an eyesore and they quickly clutter your code. (As if managing GUI code was not already enough of a challenge...)

I like to give the region the same exact name as the CLR property declaration (copy/paste it in there). That way you can see the scope, type and name when it's collapsed - which is really all you care about 95% of the time.

   #region public int ObjectDepthThreshold

    public int ObjectDepthThreshold
    {
        get { return (int)GetValue(ObjectDepthThresholdProperty); }
        set { SetValue(ObjectDepthThresholdProperty, value); }
    }

    public static readonly DependencyProperty ObjectDepthThresholdProperty = DependencyProperty.Register(
        "ObjectDepthThreshold",
        typeof(int),
        typeof(GotoXControls),
        new FrameworkPropertyMetadata((int)GotoXServiceState.OBJECT_DEPTH_THRESHOLD_DEFAULT,
            FrameworkPropertyMetadataOptions.AffectsRender,
            new PropertyChangedCallback(OnControlValueChanged)
        )
    );

    #endregion

When it's collapsed you just see

public int ObjectDepthThreshold

If I have more than one dependency property, I like to start the next #region on the very next line. That way you end up with all of them grouped together in your class, and the code is compact and readable.

BTW if you just want to peek at the declaration, mouse hover over it.

Answer 6

They can be overused, but I like them for separating private methods, public methods, properties, and instance variables.