NULLABLE TYPES FAQ _

Q: Will System.Nullable<T> generic type replace NullableTypes?

A: The short answer is no. The full answer follows.
   In 2004 .NET Framework 1.2 and C# 2.0 will be released. They implement the generic type
   System.Nullable<T> that define a standard way to deal with null values for value-types
   (C # Version 2.0 Specification July 2003, Chapter 20.5.7 The System.Nullable type).

   Due to actual limitations of Generics implementation (they miss user-specializations)
   System.Nullable<T> is only a partial solution for the built-in types. Indeed every
   built-in type have specific features that differ from other built-in types and without
   user-specializations these specific features cannot be exposed.

   So System.Nullable<T> will not replace NullableTypes instead NullableTypes for
   Whidbey will continue to provide features that are missing in System.Nullable<T> for
   built-in types, will be totally compatible with System.Nullable<T> and will enhance
   and extend System.Nullable<T> features for built-in types.

   An example of features that are missing in System.Nullable<T> follows:
   every type in NullableTypes
   - avoid the users to do a frequent explicit access to the wrapped built-in type because 
     it is very very similar (quite indistinguishable) to the corresponding built-in type
   - avoid conditional tests for null (if is null then... else...) to spread in the source 
     code because it implements Null Object pattern [1][2]
   - extends operators with the NULL semantic [3]
   

[1] Test-Driven Development - Kent Beck - Three Rivers Institute -
    http://groups.yahoo.com/group/testdrivendevelopment/files/TDD17Jul2002.pdf
[2] Refactoring: Improving the Design of Existing Code - Martin Fowler, Kent Beck et al. -
    Addison Wesley Professional - 1999 -
    http://www.refactoring.com/catalog
[3] SQL92 (ISO/IEC 9075:1992, Database Language SQL- July 30, 1992) -
    http://www.contrib.andrew.cmu.edu/%7Eshadow/sql/sql1992.txt