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                         allow_paging = false;
  46                         current_page_index = 0;
  47                         allow_custom_paging = false;
  48                         virtual_count = 0;
  49                 }
  50
  51                 public bool AllowCustomPaging {
  52                         get { return allow_custom_paging; }
  53                         set { allow_custom_paging = value; }
  54                 }
  55
  56                 public bool AllowPaging {
  57                         get { return allow_paging; }
  58                         set { allow_paging = value; }
  59                 }
  60
  61                 public int Count {
  62                         get {
  63                                 if (DataSource == null)
  64                                         return 0;
  65
  66                                 if (IsPagingEnabled == true) {
  67                                         if (IsCustomPagingEnabled == true || IsLastPage == false)
  68                                                 return PageSize;
  69
  70                                         if (IsCustomPagingEnabled == false && IsLastPage == true)
  71                                                 return FirstIndexInPage - DataSourceCount;
  72                                 }
  73
  74                                 return DataSourceCount;
  75                         }
  76                 }
  77
  78                 public int CurrentPageIndex {
  79                         get { return current_page_index; }
  80                         set { current_page_index = value; }
  81                 }
  82
  83                 public IEnumerable DataSource {
  84                         get { return source; }
  85                         set { source = value; }
  86                 }
  87
  88                 public int DataSourceCount {
  89                         get {
  90                                 if (source == null)
  91                                         return 0;
  92
  93                                 if (IsCustomPagingEnabled)
  94                                         return virtual_count;
  95
  96                                 if (source is ICollection)
  97                                         return ((ICollection) source).Count;
  98
  99                                 throw new HttpException ("The data source must implement ICollection");
 100                         }
 101                 }
 102
 103                 public int FirstIndexInPage {
 104                         get {
 105                                 if (!IsPagingEnabled || IsCustomPagingEnabled || DataSource == null)
 106                                         return 0;
 107
 108                                 return current_page_index * page_size;
 109                         }
 110                 }
 111
 112                 public bool IsCustomPagingEnabled {
 113                         get { return IsPagingEnabled && AllowCustomPaging; }
 114                 }
 115
 116                 public bool IsFirstPage {
 117                         get {
 118                                 if (!AllowPaging)
 119                                         return true;
 120
 121                                 return CurrentPageIndex == 0;
 122                         }
 123                 }
 124
 125                 public bool IsLastPage {
 126                         get {
 127                                 if (!AllowPaging)
 128                                         return true;
 129
 130                                 if (PageCount == 0)
 131                                         return false;
 132
 133                                 return CurrentPageIndex == PageCount - 1;
 134                         }
 135                 }
 136
 137                 public bool IsPagingEnabled {
 138                         get { return AllowPaging && (PageSize != 0); }
 139                 }
 140
 141                 public bool IsReadOnly {
 142                         get { return false; } // as documented
 143                 }
 144
 145                 public bool IsSynchronized {
 146                         get { return false; } // as documented
 147                 }
 148
 149                 public int PageCount {
 150                         get {
 151                                 if (DataSource == null)
 152                                         return 0;
 153
 154                                 if (!IsPagingEnabled || DataSourceCount == 0 || PageSize == 0)
 155                                         return 1;
 156
 157                                 return (DataSourceCount + PageSize - 1) / PageSize;
 158                         }
 159                 }
 160
 161                 public int PageSize {
 162                         get { return page_size; }
 163                         set { page_size = value; }
 164                 }
 165
 166                 public object SyncRoot {
 167                         get { return this; }
 168                 }
 169
 170                 public int VirtualCount {
 171                         get { return virtual_count; }
 172                         set { virtual_count = value; }
 173                 }
 174 #if NET_2_0
 175                 [MonoTODO]
 176                 public bool AllowServerPaging {
 177                         get {
 178                                 throw new NotImplementedException ();
 179                         }
 180                         set {
 181                                 throw new NotImplementedException ();
 182                         }
 183                 }
 184
 185                 [MonoTODO]
 186                 public DataSourceSelectArguments DataSourceSelectArguments {
 187                         get {
 188                                 throw new NotImplementedException ();
 189                         }
 190                         set {
 191                                 throw new NotImplementedException ();
 192                         }
 193                 }
 194                 [MonoTODO]
 195                 public DataSourceView DataSourceView {
 196                         get {
 197                                 throw new NotImplementedException ();
 198                         }
 199                         set {
 200                                 throw new NotImplementedException ();
 201                         }
 202                 }
 203
 204                 [MonoTODO]
 205                 public void SetItemCountFromPageIndex (int highestPageIndex)
 206                 {
 207                         throw new NotImplementedException ();
 208                 }
 209 #endif
 210
 211                 public void CopyTo (Array array, int index)
 212                 {
 213                         foreach (object o in source)
 214                                 array.SetValue (o, index++);
 215                 }
 216
 217                 public IEnumerator GetEnumerator ()
 218                 {
 219                         ICollection col = source as ICollection;
 220                         if (col != null)
 221                                 return GetEnumeratorEnum (col.GetEnumerator (),
 222                                                 FirstIndexInPage, FirstIndexInPage + PageSize);
 223
 224                         IList list = source as IList;
 225                         if (list != null)
 226                                 return GetListEnum (list, FirstIndexInPage,
 227                                                 FirstIndexInPage + PageSize);
 228
 229                         return source.GetEnumerator ();
 230                 }
 231
 232                 public PropertyDescriptorCollection GetItemProperties (
 233                         PropertyDescriptor [] list_accessors)
 234                 {
 235                         ITypedList typed = DataSource 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 (!AllowPaging)
 249                                 end = list.Count;
 250                         for (int i = start; i < end; i++)
 251                                 yield return list [i];
 252                 }
 253
 254                 private IEnumerator GetEnumeratorEnum (IEnumerator e, int start, int end)
 255                 {
 256                         for (int i = 0; i < start; i++)
 257                                 e.MoveNext ();
 258                         for (int i = start; (!allow_paging || i < end) && e.MoveNext (); i++)
 259                                 yield return e.Current;
 260                 }
 261         }
 262 }