Wednesday, September 04, 2013

C# : Always learn something new

Saw this on Rob Miles blog.

What does ?? mean in C# ?

You can read the full article but the essence is:

"?? provides a convenient way that I can map the null value of a nullable variable onto a specific value

int actualAge = customerAge ?? -1;
It saves us having to write code that tests for null and sets a value appropriately. 

The above statement sets the value of actualAge to the value in customerAge unless the value in customerAge is null, in which case it sets it to –1.

if (customerAge == null)
    actualAge = -1;
else    actualAge = customerAge;
In other words ?? is a short form of the above test"


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