Some of the cool new features of the C# 2.0 language are the ?? operator and nullable types.

?? returns the left operand if not null and the right otherwise. For example:

string name = null; Debug.WriteLine( "Hello " +           name ?? "George" );

...results in the output:

"Hello George"

...because the string variable "name" is null.

Nullable types, on the other hand, allow a struct (which includes built-in types like int and double) to have a null value. This comes in handy when you want to designate a default uninitialized value for a type. For instance, whereas before a developer might have used a convention where -1 or Int32.MinimumValue stood for "uninitialized", now you can just have null (which makes a lot more sense)!

Nullable types are denoted by a question mark following the type name. For instance:

double? d = 1.2; //legal because this is a nullable type! d = null;

Both of these new features are powerful enough alone, but in combination, they yield a neat new readable timesaver for things like ASP.NET server control properties!

Ever see a construct like this?

public int Count {      get      {            object count = ViewState["Count"];            return ( count != null ? (int)count : 0 );       }       set{ ViewState["Count"] = value; } }

This was a common way to communicate stored property values from ViewState with ASP.NET 1.x, but with C# 2.0 and the new language enhancements I described, we can shorten the above to this:

public int Count {       get{ return ViewState["Count"] as int? ?? 0; }       set{ ViewState["Count"] = value; } }

Cool, huh?