difference in the behavior of optionalAttribute (used to declare an optional parameter) in VS 2010 vs VS 2008

Question

A simple C# method with an optional parameter declared using the OptionalAttribute as

namespace  ClassLibrary11
{
   public class Class1
   {
      public in         


        

Answer 1

Optional parameters have been introduced with .NET 4.0 in C#, I am not sure what you are building with VS 2008 targetting an older framework, but I would say you should use them only in VS 2010 and .NET 4.0 Named and Optional Arguments