Lazy loading C#. Lazy initialization.

C# 4.0 introduced new class Lazy which provided for Lazy initialization. Lazy instantiation here means object is not created until it is get used first time. Primary use of Lazy initialization is performance improvements, reduce program memory requirements.Lazy provides thread safe object initialization.

Lasy<T> example to load object lazily

public partial class LazyClass : System.Web.UI.Page 
{
 private Lazy<List<string>> lazyItems = null; 
 public LazyClass() 
 { 
   lazyItems = new Lazy<List<string>>(GetItems); 
 } 
 public List<string> GetItems() 
 {
      List<string> items = new List<string>(); 
      for (int i = 0; i < 10; i++) 
       { 
          items.Add(string.Format("Item {0}", i)); 
       } return items;
 }

 public List<string> GetItemValues { get { return lazyItems.Value; } } 
}

So in above example we have defined private Lazy<List<string>> lazyItems = null; and then in constructor we have delegate the call to GetItems method which will return list of items. But here it will not generate and return list until we call "lazyItems.Value".