How useful is C#'s ?? operator?

Question

So I have been intrigued by the ?? operator, but have still been unable to use it. I usually think about it when I am doing something like:

var x = (someObject as someType).someMember; 

If someObject is valid and someMember is null, I could do

var x = (someObject as someType).someMember ?? defaultValue; 

but almost invariably I get into problems when someObject is null, and ?? doesn't help me make this any cleaner than doing the null check myself.

What uses have you guys found for ?? in practical situations?

Answer 1

The ?? operator is like the coalesce method in SQL, it gets you the first non-null value.

var result = value1 ?? value2 ?? value3 ?? value4 ?? defaultValue;