mcs/class/System.XML/System.Xml/XmlNodeListChildren.cs

   1 //
   2 // System.Xml.XmlNodeList
   3 //
   4 // Author:
   5 //   Kral Ferch <kral_ferch@hotmail.com>
   6 //
   7 // (C) 2002 Kral Ferch
   8 //
   9
  10 using System;
  11 using System.Collections;
  12
  13 namespace System.Xml
  14 {
  15         public class XmlNodeListChildren : XmlNodeList
  16         {
  17                 #region Enumerator
  18                 ///////////////////////////////////////////////////////////////////////
  19                 //
  20                 //      Enumerator
  21                 //
  22                 ///////////////////////////////////////////////////////////////////////
  23                 private class Enumerator : IEnumerator
  24                 {
  25                         XmlLinkedNode currentChild;
  26                         XmlLinkedNode lastChild;
  27
  28                         internal Enumerator (XmlLinkedNode lastChild)
  29                         {
  30                                 currentChild = null;
  31                                 this.lastChild = lastChild;
  32                         }
  33
  34                         public virtual object Current {
  35                                 get {
  36                                         return currentChild;
  37                                 }
  38                         }
  39
  40                         public virtual bool MoveNext()
  41                         {
  42                                 bool passedEndOfCollection = Object.ReferenceEquals(currentChild, lastChild);
  43
  44                                 if (currentChild == null) {
  45                                         currentChild = lastChild;
  46                                 }
  47
  48                                 currentChild = currentChild.NextLinkedSibling;
  49
  50                                 return passedEndOfCollection;
  51                         }
  52
  53                         public virtual void Reset()
  54                         {
  55                                 currentChild = null;
  56                         }
  57                 }
  58
  59                 #endregion
  60
  61                 #region Fields
  62                 ///////////////////////////////////////////////////////////////////////
  63                 //
  64                 //      Fields
  65                 //
  66                 ///////////////////////////////////////////////////////////////////////
  67
  68                 XmlLinkedNode lastChild;
  69
  70                 #endregion
  71
  72                 #region Constructors
  73                 ///////////////////////////////////////////////////////////////////////
  74                 //
  75                 //      Constructors
  76                 //
  77                 ///////////////////////////////////////////////////////////////////////
  78
  79                 public XmlNodeListChildren(XmlLinkedNode lastChild)
  80                 {
  81                         this.lastChild = lastChild;
  82                 }
  83
  84                 #endregion
  85
  86                 #region Properties
  87                 ///////////////////////////////////////////////////////////////////////
  88                 //
  89                 //      Properties
  90                 //
  91                 ///////////////////////////////////////////////////////////////////////
  92
  93                 public override int Count {
  94                         get {
  95                                 int count = 0;
  96
  97                                 if (lastChild != null) {
  98                                         XmlLinkedNode currentChild = lastChild.NextLinkedSibling;
  99
 100                                         count = 1;
 101                                         while (!Object.ReferenceEquals(currentChild, lastChild)) {
 102                                                 currentChild = currentChild.NextLinkedSibling;
 103                                                 count++;
 104                                         }
 105                                 }
 106
 107                                 return count;
 108                         }
 109                 }
 110
 111                 #endregion
 112
 113                 #region Methods
 114                 ///////////////////////////////////////////////////////////////////////
 115                 //
 116                 //      Methods
 117                 //
 118                 ///////////////////////////////////////////////////////////////////////
 119
 120                 public override IEnumerator GetEnumerator ()
 121                 {
 122                         return new Enumerator(lastChild);
 123                 }
 124
 125                 public override XmlNode Item (int index)
 126                 {
 127                         XmlNode requestedNode = null;
 128
 129                         // Instead of checking for && index < Count which has to walk
 130                         // the whole list to get a count, we'll just keep a count since
 131                         // we have to walk the list anyways to get to index.
 132                         if ((index >= 0) && (lastChild != null)) {
 133                                 XmlLinkedNode currentChild = lastChild.NextLinkedSibling;
 134                                 int count = 0;
 135
 136                                 while ((count < index) && !Object.ReferenceEquals(currentChild, lastChild))
 137                                 {
 138                                         currentChild = currentChild.NextLinkedSibling;
 139                                         count++;
 140                                 }
 141
 142                                 if (count == index) {
 143                                         requestedNode = currentChild;
 144                                 }
 145                         }
 146
 147                         return requestedNode;
 148                 }
 149
 150                 #endregion
 151         }
 152
 153
 154 }