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The ?? operator returns the left-hand operand if it is not null, or else it returns the right operand. For example: int? x = null; ... // y = x, unless x is null, in which case y = -1. int y = x ?? -1; The ?? operator also works with reference types: //message = param, unless param is null //in which case message = "No message" string message = param ?? "No message" ; |
Tuesday, September 25, 2007
?? operator (C#)
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1 comments:
A useful function in T-SQL is COALESCE, which takes two arguments and returns the first if it is not null and the second if the first is null.
String a = null;
String b = "abc";
String c = a ?? b;
returns "abc".
These can also be chained, so the first non-null argument is returned, so
String a = null;
String b = null;
String c = "abc";
String d = a ?? b ?? c;
returns "abc".
It's a lot easier to read than the alternative:
String d = (a != null ? a : (b != null ? b : c))
From only4gurus
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