Ternary Operator Posted on June 04, 2007 @ 18:58 csharp
I have come to become a big fan of the ternary operator... It's quite useful for replacing simple if-else statements. Ternary operator template:
( true/false expression to evaluate ) ? (true evaluation) : (false evaluation) ;
E.g.
Boolean IsMoCool = false;
String s = ( IsMoCool ) ? "Mo is cool" : "Mo is not cool";
Console.WriteLine( s );
Can you predict the result? This should print "Mo is not cool" to the console window. This happens for 2 reasons, the first is the "IsMoCool" value is initialized as false. So when the statement ( IsMoCool ) evaluated it yields a false value and executes the false condition. The 2nd reason this works is because mO is not cool! Here is maybe a better usage of the ternary operator... Let's say I have the following code...
public class TernaryDemo
{
private object _myObject;
public object MyObject
{
get
{
if( null == _myObject )
{
_myObject = new object( );
}
return _myObject;
}
}
}
This could be re-written as....
public class TernaryDemo
{
private object _myObject;
public object MyObject
{
// if _myObject hasn't been constructed yet then create an instance,
// otherwise return the constructed instance.
get { return ( null == _myObject ) ? _myObject = new object( ) : _myObject; }
}
}
Recently, I came across the ?? operator added in C# 2.0. Here's how (I think) it works...
private string _s;
public void MyMethod( )
{
string s = ( null == _s ) ? "Some Clever Text Here" : _s;
}
The above code can be re-written using ?? like this...
private string _s;
public void MyMethod( )
{
string s = _s ?? "Some Clever Text Here";
}
The ?? operator implicitly does the same operation as the ternary operator but looks much cleaner.