Just the other day I came across a C# operator that I found
particularly useful and decided to share it with everyone here at SOTC -
the ?? operator. The briefest explanation is this: ?? is used a lot like
the conditional operator (?:), except instead of any condition, it will
only check if the value on the left is null. If it is not null, it
returns the item on the left - otherwise it will return the thing on the
right.
We'll start with a really simple example - reference types:
string myString = null;
string myOtherString = myString ?? "Something Else";
Console.WriteLine(myOtherString);
//Output: "Something Else"
Here we can see a string being assigned to null. Next we use the ??
operator to assign a value to
myOtherString. Since myString is null,
the ?? operator assigns the value "Something Else" to the string.
Let's get a little more complicated and see an example using nullable
types.
int? myInt = null;
int anotherInt = myInt ?? 1234;
Console.WriteLine(anotherInt.ToString());
//Output: "1234"
The ?? operator is a great way to assign a nullable type to a
non-nullable type. If you were to attempt to assign myInt to anotherInt,
you'd receive a compile error. You could cast myInt to an integer, but
if it was null, you'd receive a runtime exception.
Granted, you can do the exact same thing with the regular conditional
operator:
int? myInt = null;
int anotherInt = myInt.HasValue ? myInt.Value : 1234;
Console.WriteLine(anotherInt.ToString());
//Output: "1234"
But, hey, that's a whole 22 extra characters - and really, it does add
up when you are doing a lot of conversions from nullable to non-nullable
types.
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