mcs/class/corlib/System/Nullable.cs

   1 //
   2 // System.Nullable
   3 //
   4 // Martin Baulig (martin@ximian.com)
   5 //
   6 // (C) 2004 Novell, Inc.
   7 //
   8
   9 using System.Reflection;
  10 using System.Collections.Generic;
  11 using System.Runtime.CompilerServices;
  12
  13 #if NET_1_2
  14 namespace System
  15 {
  16         public struct Nullable<T> : IComparable<Nullable<T>>
  17         {
  18                 T value;
  19                 bool has_value;
  20
  21                 public Nullable (T value)
  22                 {
  23                         this.value = value;
  24                         this.has_value = true;
  25                 }
  26
  27                 public bool HasValue {
  28                         get { return has_value; }
  29                 }
  30
  31                 public T Value {
  32                         get { return value; }
  33                 }
  34
  35                 public T GetValueOrDefault ()
  36                 {
  37                         if (has_value)
  38                                 return value;
  39                         return default (T);
  40                 }
  41
  42                 public T GetValueOrDefault (T def_value)
  43                 {
  44                         if (has_value)
  45                                 return value;
  46                         else
  47                                 return def_value;
  48                 }
  49
  50                 public int CompareTo (Nullable<T> other)
  51                 {
  52                         if (!has_value && other.has_value)
  53                                 return -1;
  54                         else if (has_value && !other.has_value)
  55                                 return 1;
  56                         else if (!has_value && !other.has_value)
  57                                 return 0;
  58                         else if (value == other.value)
  59                                 return 0;
  60                         else
  61                                 return 1;
  62                 }
  63         }
  64 }
  65 #endif