3

private int? _City_Id;

p4bl0
  • 3,846
  • 1
  • 22
  • 21
girish
  • 701
  • 3
  • 12
  • 22

1 Answers1

7

Without knowing your target language to respond with, in C# 2.0 the ? denotes nullable value types.

Nullable value types (denoted by a question mark, e.g. int? i = null;) which add null to the set of allowed values for any value type.

Which, as Calum points out (all credit to him), means that the variable can be assigned null. Normally primitives like int and double can't be null,

int? x = 10;
double? d = 4.108
Anthony Forloney
  • 90,123
  • 14
  • 117
  • 115
  • 3
    Which, in case that's not clear, means that the variable can be assigned "null". Normally primitives like "int" can't be null. – Calum Apr 22 '10 at 13:22