Home > Articles > Programming > C#

Using Static Methods and 'Better Betterness' in C# 6

Concluding his series on new and improved features in C# 6, Bill Wagner, author of Effective C#: 50 Specific Ways to Improve Your C#, Second Edition, discusses new syntax for static methods that will really de-clutter your code, along with improved overload resolution that reduces ambiguity by helping the compiler to make better method-overload choices.
Like this article? We recommend

In this final installment of my series of articles covering new features in C# 6, I'll discuss two more new features in the C# 6 language: static using statements, and what is often called 'Better Betterness.' The first is new syntax that reduces code clutter by making extensive use of static methods. The second is a series of improvements to the language specification and compiler implementation that determines the best match for method overloads. Constructs that previously introduced ambiguities now can often resolve to a single method.

Let's start with using static.

Static Methods

Suppose you had this line of code in your program:

var hypotenuse = Math.Sqrt(3 * 3 + 4 * 4);

It's easy to read on its own, but imagine it as part of a large class that provides a number of statistical analysis routines. In a quick scan of the code, you'd likely see the Math class name all over, cluttering up the code and making it hard to see the algorithms and other important details.

The static using feature addresses this problem. We add this statement to the using statements in the source file:

using static System.Math;

Now we can remove the Math qualifier on any invocation of a method in the Math class:

var hypotenuse = Sqrt(3 * 3 + 4 * 4);

This feature went through a couple of iterations as C# 6 neared release. You may find resources on the Web stating that you don't need to include the static keyword as part of the using statement, but that information represented the earlier proposed syntax, and it has been changed. The final syntax makes it easier to determine which using statements represent using classes, and which statements represent using namespaces.

Another change has made the feature more useful. The first proposal allowed you to add using statements only for static classes, which proved quite limiting. Some classes containing only static members had not been updated to include the static keyword (which was introduced in C# 2); System.Diagnostics.Trace is one example. It's marked sealed, but not static. However, there are no accessible constructors and no instance methods. Many other classes contain a large number of static methods and also support instances of that type. The string class is an example. Because strings are immutable, the class has many static methods that manipulate strings and return new objects. In some cases, adding a using static statement for System.String results in more readable code.

That last sentence leads into my final point about the basic syntax: In a static using statement, you must specify the fully qualified name for any class you use. You can't simply type the class name, even if you already added a using statement for the enclosing namespace. For example, the following two statements won't compile; you must specify System.Math when you're using that class:

using System;
using static Math; // CS 0246. The type or namespace type could not be found.

You also can't use a C# keyword for types in which a keyword is defined as an alias for a type:

using static System.String; // this compiles
using static string; // this generates CS1001

Static Using and Extension Methods

The C# 6 language design team took care to make sure that introducing this feature wouldn't impact the resolution for extension methods. Remember that extension methods are static methods that can be called as though they're members of the type represented by the first parameter (or any type containing an implicit conversion from the type of the first argument to the type defined for the first parameter of the method declaration).

The design goal was to make this addition to the language coexist with any code currently using extension methods. The rules governing using static and extension methods were written to ensure this goal. They may seem a bit involved, but that complexity is intentional.

Consider this query:

using System.Linq; // So that the methods in the Enumerable class are found

var squares = from n in Enumerable.Range(0, 1000)
                let root = Math.Sqrt(n)
                where root == Math.Floor(root)
                select new { Number = n, Root = root };

The where query expression resolves to System.Linq.Enumerable.Where(). The select query expression resolves to System.Linq.Enumerable.Select(). Those methods are in scope because of the using statement shown above.

I'd like to simplify the code by adding static usings so I don't have to type Math. and Enumerable. in the query above. I begin by modifying the using statements:

using static System.Linq.Enumerable;
using static System.Math;

Then I remove the name qualifiers in the query:

var squares = from n in Range(0, 1000)
                let root = Sqrt(n)
                where root == Floor(root)
                select new { Number = n, Root = root };

Notice that I could remove the using statement for the System.Linq namespace. Because I've imported all the methods in the System.Linq.Enumerable class via using static, Where and Select can be found. However, because extension methods are designed to be called as if they were instance methods, using static won't bring those methods into scope to be called as static methods. Consider these two statements:

var sequence = Range(0, 1000);
var smallNumbers = Enumerable.Where(sequence, item => item < 10);

I can't remove the Enumerable class name from the second statement. I still have the using static System.Linq.Enumerable statement, but that won't add those method names to the global scope when they're called as static methods. I also have to include the using statement for System.Linq for this example to compile. Without it, I would have to write System.Linq.Enumerable.Where(...).

The justification for this behavior is that extension methods are typically called as though they're instance methods. In the rare case where they're called as static methods, typically the reason is to resolve ambiguity. Therefore, it seems wise to force the developer to declare the class name.

Taking Advantage of 'Better Betterness'

The final feature we'll explore is often called "Better Betterness," though its official name is improved overload resolution. This feature is hard to demonstrate easily; in fact, it won't really affect your daily practices unless you look for it. In a number of areas, the compiler has improvements that enable it to pick one "best" method in C# 6, whereas in C# 5 and earlier those constructs resulted in an ambiguity. When you found such ambiguities, you would have needed to update the code to give the compiler better hints regarding the method you wanted the compiler to choose.

The one I ran into most often was when I used a method group as the argument to a method. I expected that I could write this code:

// declared elsewhere:
static Task SomeWork() { return Task.FromResult(42); }

// Call it here:

but the compiler couldn't resolve the method correctly. I'd get an error saying, "The call is ambiguous between Task.Run(Action) and Task.Run(Func<Task>)," and I'd have to change the method group to a lambda expression so the compiler would find the better method (Task.Run(Func<Task>)):

Task.Run(() => SomeWork());

When code constructs you thought would work now do work in C# 6, thank "Better Betterness."

Initial Guidance on Static and 'Better Betterness'

I saved these two features for last in this series because, while they're important, they're the features that affect my daily coding practices the least. Improved overload resolution doesn't introduce any new syntax; it just removes rough edges around code that I previously thought should work. Now it does.

By contrast, static using is a great feature, and I'm trying to make it part of my regular practices. But old habits are hard to break; I'm so accustomed to typing the class name before typing a static method that muscle memory just takes over. It's not such a significant improvement that I change existing code to take advantage of it.

This wraps up my series on the new features in C# 6. Overall, it's an impressive update to my favorite programming language. As I write this, the release candidate is out, and I expect the final release to appear soon. I truly believe the whole C# community will be excited by this release. I'm becoming much more productive as I build habits using the new features. Get your hands on the bits, and start coding.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020