Technology Corner

Home » DotNet » Lazy Loading in C# 4.0

Lazy Loading in C# 4.0

Enter your email address to follow this blog and receive notifications of new posts by email.

Join 80 other followers

Twitter updates


RSS InfoQ Feeds

  • How Google Develops New Managers
    Alex Langshur, host of Google Partners Podcasts, has organized the podcast Google HR secrets: identifying & developing great managers, interviewing Sarah Calderon, People Development at Google, on how Google selects, trains, and develops their managers. By Abel Avram
  • Presentation: Cognitive Services, Next Step in Creating Our Robot Overlords
    Harold Pulcher discusses Cognitive Services, how to get started using them, and how to incorporate speech, image, and facial recognition into an application. By Harold Pulcher
  • Presentation: Control Flow Integrity Using Hardware Counters
    Jamie Butler and Cody Pierce discuss a new system for early detection and prevention of unknown exploits. Their system uses Performance Monitoring Unit hardware to enforce coarse-grained Control Flow Integrity (CFI). They intend to prove that their approach is effective and suitable for practical use, while staying resistant to bypass. By Jamie Butler
  • JetBrains Launches GoLand Go IDE
    JetBrains has moved its Go IDE from its early access programme to market. Now branded as GoLand, the IDE extends the IntelliJ platform making its core functionality specific to Go. This follows suit with their other language-specific tools such as PyCharm for Python and RubyMine for Ruby. By Andrew Morgan
  • Panel on the Future of AI
    An SF QCon panel on the future of AI explored some issues facing machine learning today. The areas explored: critical issues facing AI right now, how has technology changed the way people are hired, how non-leading edge companies make the best use of current technologies, what the role of humans in relation to AI is, and exciting new breakthroughs on the imm […]
  • Microsoft Updates Cosmos DB with Cassandra Support and Provides Better Availability Guarantees
    Last month at Microsoft Connect 2017, Azure Cosmos DB received several new updates, including support for using the Cassandra NoSQL database API and increased guarantees for availability. With the Cassandra NoSQL database API, customers can run operations inside Cosmos DB on a data model. The availability guarantee moves from 99.99 percent to 99.999 percent. […]
  • Article: Approximate Computing on WSO2: Explaining Approximation Algorithms in an Applied Setting
    In this article, we describe an example real world application of API monitoring which gets benefit by using approximate stream processing. We developed the application on top of WSO2 Stream Processor as Siddhi extension. Siddhi is the complex event processing library which acts as the event processing engine of WSO2 Stream Processor. By Chamod Samarajeewa
  • Rust in Visual Studio and VS Code
    Daniel Griffen has released a preview version of a Rust language service for Visual Studio. This plugin requires Visual Studio 2017 Preview, an experimental release stream for testing new VS features. By Jonathan Allen
  • Article: Key Takeaway Points and Lessons Learned from QCon San Francisco 2017
    The eleventh annual QCon San Francisco was the biggest yet, bringing together over 1,800 team leads, architects, project managers, and engineering directors. By Abel Avram
  • Article: Q&A With Eberhard Wolff On the Book “A Practical Guide to Continuous Delivery”
    Eberhard Wolff speaks with InfoQ about his work "Continuous Delivery: A Practical Guide", where we detail some of the major concepts behind successful CD adoption and the ripple-effect it can have on developer productivity and quality of service. By Dylan Raithel

Lazy loading is a pattern which delay initialization of object. C# 4.0 introduced new class which defers the creation of expensive objects when not in use. In this article I’ll explain the use of Lazy<T> class. Suppose we have Customer class and one customer can have many Accounts, if you want show Accounts for one customer, you need to load accounts associated with customer. Loading of accounts can make performance hit badly if data is huge while initializing Customer object. To avoid this situation Lazy loading comes for rescue. Loading of Accounts will only happen when you will use accounts list. This will make sure fast loading of customer object and give performance boost to application.

Here I am explaining example of Customer and Accounts relationship by Lazy loading:

First we create entity classes of Customer and Account:

public class Account
        public int Id { get; set; }

    public class Customer
        public string Name { get; set; }
        public int CustomerId { get; set; }

        public List GetAccounts()
            return lazylist.Value;

        Lazy<List<Account>> lazylist;

        public Customer(string name, int id)
            Console.WriteLine("Initializing Customer Object");
            Name = name;
            CustomerId = id;
            lazylist = new Lazy<List<Account>>(() => { return GetAccountList(id); });
            Console.WriteLine("Initialization done");

        private List GetAccountList(int id)
            Console.WriteLine("Loading Accounts:");
            List list = new List();
            Parallel.For(100, 110, (int i) =>
                Account a = new Account();
                a.Id = i;
            return list;

In the constructor of customer class, properties are initializing and declaring lazylist object, which is generic List of account and filled by GetAccountList method. This method will only call when lazylist object will be use. Below is main method which shows behavior of lazy loading:

static void Main(string[] args)

            Customer cust = new Customer("Neeraj", 1);//constructor should not load accounts

            foreach(Account ac in cust.GetAccounts())// it will actually load accounts, ie. lazy loading


In above code when this statement foreach(Account ac in cust.GetAccounts()) is called then acccount list is filled.


Initializing Customer Object

Initialization done

Loading Accounts:











Syntax of Lazy<T> object

        public Lazy();
        public Lazy(bool isThreadSafe);
        public Lazy(Func valueFactory);
        public Lazy(LazyThreadSafetyMode mode);
        public Lazy(Func valueFactory, bool isThreadSafe);
        public Lazy(Func valueFactory, LazyThreadSafetyMode mode);

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Blogs I Follow

%d bloggers like this: