http://blogs.msdn.com/b/abhinaba/archive/2006/12/21/creating-immutable-types.aspxSomeone asked on a C# DL " How do I create an immutable type " The answer was obviously by creating a type in which you don't allow writeable fields or properties or have methods that change the state of the type. However, the questions started revolvingen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)http://blogs.msdn.com/b/abhinaba/archive/2006/12/21/creating-immutable-types.aspx#9823040Tue, 07 Jul 2009 21:41:34 GMT91d46819-8472-40ad-a661-2c78acb4018c:9823040j<p>void Main(){</p> <p>var emp = new Employee(&quot;bob&quot;, 10000);</p> <p>MakeNull(emp);</p> <p>Console.WriteLine(emp.Name);//null reference exception</p> <p>}</p> <p>void MakeNull(Employee emp)</p> <p>{</p> <p>emp = null;</p> <p>}</p> <p>classes can't be truly immutable in C#</p> <div style="clear:both;"></div><img src="http://blogs.msdn.com/aggbug.aspx?PostID=9823040" width="1" height="1">http://blogs.msdn.com/b/abhinaba/archive/2006/12/21/creating-immutable-types.aspx#1345361Fri, 22 Dec 2006 09:35:14 GMT91d46819-8472-40ad-a661-2c78acb4018c:1345361Abhinaba Basu [MSFT]<p>Oops missed readonly :(</p> <p>I have updated the code.</p> <div style="clear:both;"></div><img src="http://blogs.msdn.com/aggbug.aspx?PostID=1345361" width="1" height="1">http://blogs.msdn.com/b/abhinaba/archive/2006/12/21/creating-immutable-types.aspx#1342561Fri, 22 Dec 2006 00:51:40 GMT91d46819-8472-40ad-a661-2c78acb4018c:1342561PBR<p>Hmmm...why not use the readonly keyword on the name and salary fields?</p> <p>i.e.: readonly string salary;</p> <p>-- PBR</p> <div style="clear:both;"></div><img src="http://blogs.msdn.com/aggbug.aspx?PostID=1342561" width="1" height="1">