So during my quest to understand NHibernate I came across a new keyword in C#. (well kind of new, it’s actually an old keyword but used in a different manner specifically for generic types.)

Here’s my problem… When you define a generic type it does not assume it to be either of a reference type or value type. And I do not want to force my type to be a reference type, I want it to be generic. But in a scenario where I have to return an blank or “null” value, that assumption says that the type has to be a reference type…

Here’s what I’m talking about:

The return null statement is making the assumption that T is a reference type. (I don’t want to make this assumption!) In this case I would like to return the default value for reference types and value types without having to create 2 generic types. One for each!

So I can use the default( T ) statement which will return a null for reference types, and a 0 for value types! Problem solved.

public T SearchFor( Int32 id ) 
{
  using( ISessionTransaction dbStore = _manager.StartTransaction( ) ) 
  {
    try 
    {
      return ( T )dbStore.Session.Load( typeof( T ), id );
    }
    catch( ObjectNotFoundException ) 
    {
      return default( T );
    }
    catch( ADOException ) 
    {
      if( dbStore != null && null != dbStore.Transaction ) 
      {
        dbStore.Transaction.Rollback( );
        throw;
      }
    }
  }
}

See MSDN for more information… http://msdn2.microsoft.com/en-us/library/xwth0h0d(VS.80).aspx

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