In Visual Studio 2008 and 2010 we used to be able to see object members defined in the constructor and commented using a "field comment" in the Intellisense results. Since the change to Visual Studio 2012 these members are no longer included.
According to msdn documentation for VS 2012 this should still be working:
In the Remarks section it states:
When you're documenting a constructor function, the <field> element must appear immediately before the field declaration. The name attribute must match the field name that's used in the source code. For object members, the name attribute can be omitted if the <field> element appears immediately before the object member declaration.