mcs/class/System.Web/System.Web.UI.WebControls/PagedDataSource.cs

   1 // System.Web.UI.WebControls.PagedDataSource.cs
   2 //
   3 // Author: Duncan Mak (duncan@novell.com)
   4 //         Jackson Harper  (jackson@ximian.com)
   5 //
   6 // Copyright (C) 2005 Novell, Inc (http://www.novell.com)
   7 //
   8 // Permission is hereby granted, free of charge, to any person obtaining
   9 // a copy of this software and associated documentation files (the
  10 // "Software"), to deal in the Software without restriction, including
  11 // without limitation the rights to use, copy, modify, merge, publish,
  12 // distribute, sublicense, and/or sell copies of the Software, and to
  13 // permit persons to whom the Software is furnished to do so, subject to
  14 // the following conditions:
  15 //
  16 // The above copyright notice and this permission notice shall be
  17 // included in all copies or substantial portions of the Software.
  18 //
  19 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  20 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  21 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  22 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  23 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  24 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  25 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  26 //
  27
  28 using System.Collections;
  29 using System.ComponentModel;
  30 using System.Security.Permissions;
  31
  32 namespace System.Web.UI.WebControls {
  33
  34         // CAS - no inheritance demand required because the class is sealed
  35         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  36         public sealed class PagedDataSource : ICollection, IEnumerable, ITypedList
  37         {
  38                 int page_size, current_page_index, virtual_count;
  39                 bool allow_paging, allow_custom_paging;
  40                 IEnumerable source;
  41
  42                 public PagedDataSource ()
  43                 {
  44                         page_size = 10;
  45                 }
  46
  47                 public bool AllowCustomPaging {
  48                         get { return allow_custom_paging; }
  49                         set { allow_custom_paging = value; }
  50                 }
  51
  52                 public bool AllowPaging {
  53                         get { return allow_paging; }
  54                         set { allow_paging = value; }
  55                 }
  56
  57                 public int Count {
  58                         get {
  59                                 if (source == null)
  60                                         return 0;
  61
  62                                 if (IsPagingEnabled) {
  63                                         if (IsCustomPagingEnabled || !IsLastPage)
  64                                                 return page_size;
  65                                         return DataSourceCount - FirstIndexInPage;
  66                                 }
  67
  68                                 return DataSourceCount;
  69                         }
  70                 }
  71
  72                 public int CurrentPageIndex {
  73                         get { return current_page_index; }
  74                         set { current_page_index = value; }
  75                 }
  76
  77                 public IEnumerable DataSource {
  78                         get { return source; }
  79                         set { source = value; }
  80                 }
  81
  82                 public int DataSourceCount {
  83                         get {
  84                                 if (source == null)
  85                                         return 0;
  86
  87                                 if (IsCustomPagingEnabled)
  88                                         return virtual_count;
  89
  90                                 if (source is ICollection)
  91                                         return ((ICollection) source).Count;
  92
  93                                 throw new HttpException ("The data source must implement ICollection");
  94                         }
  95                 }
  96
  97                 public int FirstIndexInPage {
  98                         get {
  99                                 if (!IsPagingEnabled || IsCustomPagingEnabled || source == null)
 100                                         return 0;
 101
 102                                 return current_page_index * page_size;
 103                         }
 104                 }
 105
 106                 public bool IsCustomPagingEnabled {
 107                         get { return IsPagingEnabled && allow_custom_paging; }
 108                 }
 109
 110                 public bool IsFirstPage {
 111                         get {
 112                                 if (!allow_paging)
 113                                         return true;
 114
 115                                 return current_page_index == 0;
 116                         }
 117                 }
 118
 119                 public bool IsLastPage {
 120                         get {
 121                                 if (!allow_paging || page_size == 0)
 122                                         return true;
 123
 124                                 return  (current_page_index == (PageCount - 1));
 125                         }
 126                 }
 127
 128                 public bool IsPagingEnabled {
 129                         get { return (allow_paging && page_size != 0); }
 130                 }
 131
 132                 public bool IsReadOnly {
 133                         get { return false; } // as documented
 134                 }
 135
 136                 public bool IsSynchronized {
 137                         get { return false; } // as documented
 138                 }
 139
 140                 public int PageCount {
 141                         get {
 142                                 if (source == null)
 143                                         return 0;
 144
 145                                 if (!IsPagingEnabled || DataSourceCount == 0 || page_size == 0)
 146                                         return 1;
 147
 148                                 return (DataSourceCount + page_size - 1) / page_size;
 149                         }
 150                 }
 151
 152                 public int PageSize {
 153                         get { return page_size; }
 154                         set { page_size = value; }
 155                 }
 156
 157                 public object SyncRoot {
 158                         get { return this; }
 159                 }
 160
 161                 public int VirtualCount {
 162                         get { return virtual_count; }
 163                         set { virtual_count = value; }
 164                 }
 165 #if NET_2_0
 166                 [MonoTODO]
 167                 public bool AllowServerPaging {
 168                         get {
 169                                 throw new NotImplementedException ();
 170                         }
 171                         set {
 172                                 throw new NotImplementedException ();
 173                         }
 174                 }
 175
 176                 [MonoTODO]
 177                 public DataSourceSelectArguments DataSourceSelectArguments {
 178                         get {
 179                                 throw new NotImplementedException ();
 180                         }
 181                         set {
 182                                 throw new NotImplementedException ();
 183                         }
 184                 }
 185                 [MonoTODO]
 186                 public DataSourceView DataSourceView {
 187                         get {
 188                                 throw new NotImplementedException ();
 189                         }
 190                         set {
 191                                 throw new NotImplementedException ();
 192                         }
 193                 }
 194
 195                 [MonoTODO]
 196                 public void SetItemCountFromPageIndex (int highestPageIndex)
 197                 {
 198                         throw new NotImplementedException ();
 199                 }
 200 #endif
 201
 202                 public void CopyTo (Array array, int index)
 203                 {
 204                         foreach (object o in source)
 205                                 array.SetValue (o, index++);
 206                 }
 207
 208                 public IEnumerator GetEnumerator ()
 209                 {
 210                         // IList goes first, as it implements ICollection
 211                         IList list = source as IList;
 212                         int first = 0;
 213                         int count;
 214                         int limit;
 215                         if (list != null) {
 216                                 first = FirstIndexInPage;
 217                                 count = ((ICollection) source).Count;
 218                                 limit = ((first + page_size) > count) ? (count - first) : page_size;
 219                                 return GetListEnum (list, first, first + limit);
 220                         }
 221
 222                         ICollection col = source as ICollection;
 223                         if (col != null) {
 224                                 first = FirstIndexInPage;
 225                                 count = col.Count;
 226                                 limit = ((first + page_size) > count) ? (count - first) : page_size;
 227                                 return GetEnumeratorEnum (col.GetEnumerator (), first, first + page_size);
 228                         }
 229
 230                         return source.GetEnumerator ();
 231                 }
 232
 233                 public PropertyDescriptorCollection GetItemProperties (PropertyDescriptor [] list_accessors)
 234                 {
 235                         ITypedList typed = source as ITypedList;
 236                         if (typed == null)
 237                                 return null;
 238                         return typed.GetItemProperties (list_accessors);
 239                 }
 240
 241                 public string GetListName (PropertyDescriptor [] list_accessors)
 242                 {
 243                         return String.Empty; // as documented
 244                 }
 245
 246                 private IEnumerator GetListEnum (IList list, int start, int end)
 247                 {
 248                         if (!allow_paging)
 249                                 end = list.Count;
 250                         else if (start >= list.Count)
 251                                 yield break;
 252
 253                         for (int i = start; i < end; i++)
 254                                 yield return list [i];
 255                 }
 256
 257                 private IEnumerator GetEnumeratorEnum (IEnumerator e, int start, int end)
 258                 {
 259                         for (int i = 0; i < start; i++)
 260                                 e.MoveNext ();
 261                         for (int i = start; (!allow_paging || i < end) && e.MoveNext (); i++)
 262                                 yield return e.Current;
 263                 }
 264         }
 265 }
 266