Design Patterns - Generic Singleton Pattern

5 Comments

• Why not use new() instead? Is there some reason you had to use reflection?
  
  Change your public class declaration to:
  public class Singleton where T :class, new()
  
  then change your _instance instantiation to:
  private static readonly T _instance = new T();
  
  

• Hi David,
  what about my solution?
  
  public abstract class Singleton where T : class, new()
  {
  protected Singleton() { }
  private static readonly object _sync = new object();
  private static T _instance;
  public static T Instance
  {
  get
  {
  if (_instance == null)
  {
  lock (_sync)
  {
  if (_instance == null)
  _instance = new T();
  }
  }
  return _instance;
  }
  }
  }
  
  // usage sample:
  public class MyClass : Singleton
  {
  protected MyClass() {}
  
  // ...
  }
  
  
  Let me know!
  

• Oups.... pls, remove my previous comment: it's sooooooooo bad!
  1) double-check locking is outdated :-)
  2) : where new() and protected paremeterless constructor???
  
  Maybe i was drunk!!!
  Sorry.
  

• I figured I was missing some basic component of what you were trying to accomplish. Makes perfect sense now.
  

• Ah - good point. Sorry I missed that.