Click here to Skip to main content
15,885,365 members
Articles / Programming Languages / C#

Simple Singleton Pattern in C#

Rate me:
Please Sign up or sign in to vote.
5.00/5 (14 votes)
9 Jul 2011CPOL 16.5K   4  
The easiest singleton pattern is the one you used to the lock object itself.Creating any variable as static readonly and initializing it directly (or via a static constructor) will already make it singleton.Also, considering that "lock" clears all the caches, you don't need to declare the...

Alternatives

Members may post updates or alternatives to this current article in order to show different approaches or add new features.

Please Sign up or sign in to vote.
7 Nov 2011Henry.Ayoola
Jon Skeet has written an article giving six singleton implementations in C#. The simplest only works in .NET 4:public sealed class Singleton{ private static readonly Lazy lazy = new Lazy(() => new Singleton()); public static Singleton Instance {...
Please Sign up or sign in to vote.
6 Nov 2011Eddy Vluggen
I'll be shot for posting this as an alternative, but I'm too curious for the answer.Shashank Bisen wrote: Ensure a class only has one instance.Provide a global point of access to it....As stated above, a singleton is a class that can be instantiated once, and only once.What is the...
Please Sign up or sign in to vote.
6 Jul 2011Shashank Bisen 8 alternatives  
A brief explaination of how to implement the Singleton pattern class in multithreading environment.
Please Sign up or sign in to vote.
30 Oct 2011Paulo Zemek
The problem with alternative 3 and 4 is that it is not multi-threaded.Two threads may check for null, then the two will create the new instance. The race condition only happens at the first accesses. If a single thread accesses the object, then later many threads do the access, there is no...
Please Sign up or sign in to vote.
8 Jul 2011schamese
This should do it as well:class Singleton { public static readonly Singleton m_Instance = new Singleton(); // Prevent instance creation from other classes private Singleton() { } public static Singleton Instance { get { return m_Instance; } }}And it is "Singleton",...
Please Sign up or sign in to vote.
27 Oct 2011ForgaSw
Another alternative: class Singleton { public static Singleton m_Instance; //Prevent instance creation from other classes private Singleton() { } public static Singleton Instance { get { return m_Instance ?? (m_Instance = new Singleton()); } ...
Please Sign up or sign in to vote.
6 Nov 2011Kabwla.Phone
Make it a generic class and fix your problem forever. This works because the compiler turns the generic into a new class (something like SigletonManagerOfTypeParamterTypeName). So the static variables are not shared amongst instances...public static class Singleton where...
Please Sign up or sign in to vote.
8 Nov 2011jamesklett
You should do it like this:public sealed class MySingleton { public static readonly MySingleton SharedInstance = new MySingleton (); private MySingleton () : base() { }}

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Software Developer (Senior) Microsoft
United States United States
I started to program computers when I was 11 years old, as a hobbyist, programming in AMOS Basic and Blitz Basic for Amiga.
At 12 I had my first try with assembler, but it was too difficult at the time. Then, in the same year, I learned C and, after learning C, I was finally able to learn assembler (for Motorola 680x0).
Not sure, but probably between 12 and 13, I started to learn C++. I always programmed "in an object oriented way", but using function pointers instead of virtual methods.

At 15 I started to learn Pascal at school and to use Delphi. At 16 I started my first internship (using Delphi). At 18 I started to work professionally using C++ and since then I've developed my programming skills as a professional developer in C++ and C#, generally creating libraries that help other developers do their work easier, faster and with less errors.

Want more info or simply want to contact me?
Take a look at: http://paulozemek.azurewebsites.net/
Or e-mail me at: paulozemek@outlook.com

Codeproject MVP 2012, 2015 & 2016
Microsoft MVP 2013-2014 (in October 2014 I started working at Microsoft, so I can't be a Microsoft MVP anymore).

Comments and Discussions