mcs/class/System.Web.Extensions/System.Web.UI.WebControls/ListViewPagedDataSource.cs

   1 //
   2 // System.Web.UI.WebControls.ListView
   3 //
   4 // Authors:
   5 //   Marek Habersack (mhabersack@novell.com)
   6 //
   7 // (C) 2007-2008 Novell, Inc
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30 #if NET_3_5
  31 using System;
  32 using System.Collections;
  33 using System.ComponentModel;
  34
  35 namespace System.Web.UI.WebControls
  36 {
  37         public class ListViewPagedDataSource : ICollection, IEnumerable, ITypedList
  38         {
  39                 sealed class ListEnumerator : IEnumerator
  40                 {
  41                         int index;
  42                         int startIndex;
  43                         int end;
  44                         IList list;
  45
  46                         public object Current {
  47                                 get { return list [startIndex + index]; }
  48                         }
  49
  50                         public ListEnumerator (IList list, int startIndex, int end)
  51                         {
  52                                 this.list = list;
  53                                 this.index = -1;
  54                                 this.startIndex = startIndex;
  55                                 this.end = startIndex + end;
  56                         }
  57
  58                         public bool MoveNext ()
  59                         {
  60                                 index++;
  61                                 return (startIndex + index) < end;
  62                         }
  63
  64                         // See:
  65                         // http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.listviewpageddatasource.getenumerator.aspx
  66                         // (Note 1)
  67                         public void Reset ()
  68                         {
  69                                 index = -1;
  70                         }
  71                 }
  72
  73                 sealed class CollectionEnumerator : IEnumerator
  74                 {
  75                         int index;
  76                         int startIndex;
  77                         int end;
  78                         ICollection collection;
  79                         IEnumerator enumerator;
  80
  81                         public object Current {
  82                                 get {
  83                                         if (enumerator != null)
  84                                                 return enumerator.Current;
  85
  86                                         return null;
  87                                 }
  88                         }
  89
  90                         public CollectionEnumerator (ICollection collection, int startIndex, int end)
  91                         {
  92                                 this.collection = collection;
  93                                 this.index = -1;
  94                                 this.startIndex = startIndex;
  95                                 this.end = end;
  96                         }
  97
  98                         public bool MoveNext ()
  99                         {
 100                                 if (enumerator == null) {
 101                                         enumerator = collection.GetEnumerator ();
 102                                         for (int i = 0; i < startIndex; i++)
 103                                                 enumerator.MoveNext ();
 104                                 }
 105
 106                                 index++;
 107                                 enumerator.MoveNext ();
 108                                 return (startIndex + index) < end;
 109                         }
 110
 111                         // See:
 112                         // http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.listviewpageddatasource.getenumerator.aspx
 113                         // (Note 1)
 114                         public void Reset ()
 115                         {
 116                                 index = -1;
 117                                 enumerator = null;
 118                         }
 119                 }
 120
 121                 public ListViewPagedDataSource ()
 122                 {
 123                         StartRowIndex = 0;
 124                         MaximumRows = 0;
 125                         AllowServerPaging = false;
 126                         TotalRowCount = 0;
 127                 }
 128
 129                 public void CopyTo (Array array, int index)
 130                 {
 131                 }
 132
 133                 public IEnumerator GetEnumerator ()
 134                 {
 135                         IEnumerable ds = DataSource;
 136
 137                         if (ds == null)
 138                                 return null;
 139
 140                         IList list = ds as IList;
 141                         if (list != null)
 142                                 return new ListEnumerator (list, AllowServerPaging ? 0 : StartRowIndex, Count);
 143
 144                         ICollection collection = ds as ICollection;
 145                         if (collection != null)
 146                                 return new CollectionEnumerator (collection, AllowServerPaging ? 0 : StartRowIndex, Count);
 147
 148                         return ds.GetEnumerator ();
 149                 }
 150
 151                 public PropertyDescriptorCollection GetItemProperties (PropertyDescriptor [] listAccessors)
 152                 {
 153                         IEnumerable ds = DataSource;
 154
 155                         if (ds == null || !(ds is ITypedList))
 156                                 return null;
 157
 158                         return ((ITypedList) ds).GetItemProperties (listAccessors);
 159                 }
 160
 161                 public string GetListName (PropertyDescriptor [] listAccessors)
 162                 {
 163                         return String.Empty;
 164                 }
 165
 166                 public bool AllowServerPaging {
 167                         get;
 168                         set;
 169                 }
 170
 171                 public int Count {
 172                         get {
 173                                 IEnumerable ds = DataSource;
 174                                 if (ds == null)
 175                                         return 0;
 176
 177                                 bool onLastPage = OnLastPage;
 178                                 int maxRows = MaximumRows;
 179                                 if (!onLastPage && maxRows >= 0)
 180                                         return maxRows;
 181
 182                                 // LAMESPEC: MSDN says that DataSourceCount should be subtracted
 183                                 // from StartRowIndex
 184                                 return DataSourceCount - StartRowIndex;
 185                         }
 186                 }
 187
 188                 public IEnumerable DataSource {
 189                         get;
 190                         set;
 191                 }
 192
 193                 public int DataSourceCount {
 194                         get {
 195                                 IEnumerable ds = DataSource;
 196                                 if (ds == null)
 197                                         return 0;
 198
 199                                 if (!(ds is ICollection))
 200                                         throw new InvalidOperationException ("The data source object does not implement the System.Collections..::.ICollection interface.");
 201
 202                                 if (IsServerPagingEnabled)
 203                                         return TotalRowCount;
 204
 205                                 return ((ICollection) ds).Count;
 206                         }
 207                 }
 208
 209                 public bool IsReadOnly {
 210                         get { return false; }
 211                 }
 212
 213                 public bool IsServerPagingEnabled {
 214                         get { return AllowServerPaging; }
 215                 }
 216
 217                 public bool IsSynchronized {
 218                         get { return false; }
 219                 }
 220
 221                 public int MaximumRows {
 222                         get;
 223                         set;
 224                 }
 225
 226                 public int StartRowIndex {
 227                         get;
 228                         set;
 229                 }
 230
 231                 public object SyncRoot {
 232                         get { return this; }
 233                 }
 234
 235                 public int TotalRowCount {
 236                         get;
 237                         set;
 238                 }
 239
 240                 bool OnLastPage {
 241                         get { return ((StartRowIndex + MaximumRows) >= DataSourceCount); }
 242                 }
 243
 244         }
 245 }
 246 #endif