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

   1 /**\r
   2  * Namespace: System.Web.UI.WebControls\r
   3  * Class:     PagedDataSource\r
   4  *\r
   5  * Author:  Gaurav Vaish\r
   6  * Maintainer: gvaish@iitk.ac.in\r
   7  * Contact: <my_scripts2001@yahoo.com>, <gvaish@iitk.ac.in>\r
   8  * Implementation: yes\r
   9  * Status:  100%\r
  10  *\r
  11  * (C) Gaurav Vaish (2002)\r
  12  */\r
  13 \r
  14 using System;\r
  15 using System.ComponentModel;\r
  16 using System.Collections;\r
  17 using System.Web;\r
  18 using System.Web.UI;\r
  19 \r
  20 namespace System.Web.UI.WebControls\r
  21 {\r
  22         public sealed class PagedDataSource : ICollection, IEnumerable, ITypedList\r
  23         {\r
  24                 private int  pageSize;\r
  25                 private bool allowPaging;\r
  26                 private int  currentPageIndex;\r
  27                 private bool allowCustomPaging;\r
  28                 private int  virtualCount;\r
  29 \r
  30                 private IEnumerable dataSource;\r
  31 \r
  32                 public PagedDataSource()\r
  33                 {\r
  34                         Initialize();\r
  35                 }\r
  36 \r
  37                 private void Initialize()\r
  38                 {\r
  39                         pageSize          = 10;\r
  40                         allowPaging       = false;\r
  41                         currentPageIndex  = 0;\r
  42                         allowCustomPaging = false;\r
  43                         virtualCount      = 0;\r
  44                 }\r
  45 \r
  46                 public bool AllowCustomPaging\r
  47                 {\r
  48                         get\r
  49                         {\r
  50                                 return allowCustomPaging;\r
  51                         }\r
  52                         set\r
  53                         {\r
  54                                 allowCustomPaging = value;\r
  55                         }\r
  56                 }\r
  57 \r
  58                 public bool AllowPaging\r
  59                 {\r
  60                         get\r
  61                         {\r
  62                                 return allowPaging;\r
  63                         }\r
  64                         set\r
  65                         {\r
  66                                 allowPaging = value;\r
  67                         }\r
  68                 }\r
  69 \r
  70                 public int Count\r
  71                 {\r
  72                         get\r
  73                         {\r
  74                                 if(dataSource != null)\r
  75                                 {\r
  76                                         if(IsPagingEnabled)\r
  77                                         {\r
  78                                                 return DataSourceCount;\r
  79                                         }\r
  80                                         if(IsCustomPagingEnabled)\r
  81                                         {\r
  82                                                 return pageSize;\r
  83                                         }\r
  84                                         if(IsLastPage)\r
  85                                         {\r
  86                                                 return (DataSourceCount - FirstIndexInPage);\r
  87                                         }\r
  88                                         return pageSize;\r
  89                                 }\r
  90                                 return 0;\r
  91                         }\r
  92                 }\r
  93 \r
  94                 public int CurrentPageIndex\r
  95                 {\r
  96                         get\r
  97                         {\r
  98                                 return currentPageIndex;\r
  99                         }\r
 100 \r
 101                         set\r
 102                         {\r
 103                                 currentPageIndex = value;\r
 104                         }\r
 105                 }\r
 106 \r
 107                 public IEnumerable DataSource\r
 108                 {\r
 109                         get\r
 110                         {\r
 111                                 return dataSource;\r
 112                         }\r
 113                         set\r
 114                         {\r
 115                                 dataSource = value;\r
 116                         }\r
 117                 }\r
 118 \r
 119                 public int DataSourceCount\r
 120                 {\r
 121                         get\r
 122                         {\r
 123                                 if(dataSource != null)\r
 124                                 {\r
 125                                         if(IsCustomPagingEnabled)\r
 126                                         {\r
 127                                                 return virtualCount;\r
 128                                         }\r
 129                                         if(dataSource is ICollection)\r
 130                                         {\r
 131                                                 return ((ICollection)dataSource).Count;\r
 132                                         }\r
 133                                         throw new HttpException(HttpRuntime.FormatResourceString("PagedDataSource_Cannot_Get_Count"));\r
 134                                 }\r
 135                                 return 0;\r
 136                         }\r
 137                 }\r
 138 \r
 139                 public int FirstIndexInPage\r
 140                 {\r
 141                         get\r
 142                         {\r
 143                                 if(dataSource != null && IsPagingEnabled && IsCustomPagingEnabled)\r
 144                                 {\r
 145                                         return (currentPageIndex * pageSize);\r
 146                                 }\r
 147                                 return 0;\r
 148                         }\r
 149                 }\r
 150 \r
 151                 public bool IsCustomPagingEnabled\r
 152                 {\r
 153                         get\r
 154                         {\r
 155                                 return (IsPagingEnabled && allowCustomPaging);\r
 156                         }\r
 157                 }\r
 158 \r
 159                 public bool IsFirstPage\r
 160                 {\r
 161                         get\r
 162                         {\r
 163                                 return (!IsPagingEnabled || (CurrentPageIndex == 0));\r
 164                         }\r
 165                 }\r
 166 \r
 167                 public bool IsLastPage\r
 168                 {\r
 169                         get\r
 170                         {\r
 171                                 return (!IsPagingEnabled || (CurrentPageIndex == PageCount));\r
 172                         }\r
 173                 }\r
 174 \r
 175                 public bool IsPagingEnabled\r
 176                 {\r
 177                         get\r
 178                         {\r
 179                                 return (allowPaging && pageSize != 0);\r
 180                         }\r
 181                 }\r
 182 \r
 183                 public bool IsReadOnly\r
 184                 {\r
 185                         get\r
 186                         {\r
 187                                 return false;\r
 188                         }\r
 189                 }\r
 190 \r
 191                 public bool IsSynchronized\r
 192                 {\r
 193                         get\r
 194                         {\r
 195                                 return false;\r
 196                         }\r
 197                 }\r
 198 \r
 199                 public int PageCount\r
 200                 {\r
 201                         get\r
 202                         {\r
 203                                 if(dataSource != null)\r
 204                                 {\r
 205                                         int total = DataSourceCount;\r
 206                                         if(!IsPagingEnabled)\r
 207                                         {\r
 208                                                 return total;\r
 209                                         }\r
 210                                         return (total + pageSize - 1)/pageSize;\r
 211                                 }\r
 212                                 return 0;\r
 213                         }\r
 214                 }\r
 215 \r
 216                 public int PageSize\r
 217                 {\r
 218                         get\r
 219                         {\r
 220                                 return pageSize;\r
 221                         }\r
 222                         set\r
 223                         {\r
 224                                 pageSize = value;\r
 225                         }\r
 226                 }\r
 227 \r
 228                 public object SyncRoot\r
 229                 {\r
 230                         get\r
 231                         {\r
 232                                 return this;\r
 233                         }\r
 234                 }\r
 235 \r
 236                 public int VirtualCount\r
 237                 {\r
 238                         get\r
 239                         {\r
 240                                 return virtualCount;\r
 241                         }\r
 242                         set\r
 243                         {\r
 244                                 virtualCount = value;\r
 245                         }\r
 246                 }\r
 247 \r
 248                 public void CopyTo(Array array, int index)\r
 249                 {\r
 250                         foreach(object current in this)\r
 251                         {\r
 252                                 array.SetValue(array, index++);\r
 253                         }\r
 254                 }\r
 255 \r
 256                 public IEnumerator GetEnumerator()\r
 257                 {\r
 258                         int fInd = FirstIndexInPage;\r
 259                         int count = -1;\r
 260                         if(dataSource is ICollection)\r
 261                         {\r
 262                                 count = Count;\r
 263                         }\r
 264 \r
 265                         if(dataSource is IList)\r
 266                         {\r
 267                                 return (new PrivateListEnumerator((IList)dataSource, fInd, count));\r
 268                         }\r
 269                         if(dataSource is Array)\r
 270                         {\r
 271                                 return (new PrivateArrayEnumerator((object[])dataSource, fInd, count));\r
 272                         }\r
 273                         if(dataSource is ICollection)\r
 274                         {\r
 275                                 return (new PrivateICollectionEnumerator((ICollection)dataSource, fInd, count));\r
 276                         }\r
 277                         if(allowCustomPaging)\r
 278                         {\r
 279                                 return (new PrivateIEnumeratorEnumerator(dataSource.GetEnumerator(), Count));\r
 280                         }\r
 281                         return dataSource.GetEnumerator();\r
 282                 }\r
 283 \r
 284                 class PrivateIEnumeratorEnumerator : IEnumerator\r
 285                 {\r
 286                         private int index;\r
 287                         private int max;\r
 288 \r
 289                         private IEnumerator enumerator;\r
 290 \r
 291                         public PrivateIEnumeratorEnumerator(IEnumerator enumerator, int count)\r
 292                         {\r
 293                                 this.enumerator = enumerator;\r
 294                                 index = -1;\r
 295                                 max   = count;\r
 296                         }\r
 297 \r
 298                         public bool MoveNext()\r
 299                         {\r
 300                                 enumerator.MoveNext();\r
 301                                 index++;\r
 302                                 return (index < max);\r
 303                         }\r
 304 \r
 305                         public void Reset()\r
 306                         {\r
 307                                 index = -1;\r
 308                                 enumerator.Reset();\r
 309                         }\r
 310 \r
 311                         public object Current\r
 312                         {\r
 313                                 get\r
 314                                 {\r
 315                                         return enumerator.Current;\r
 316                                 }\r
 317                         }\r
 318                 }\r
 319 \r
 320                 class PrivateICollectionEnumerator : IEnumerator\r
 321                 {\r
 322                         private int index;\r
 323                         private int start;\r
 324                         private int max;\r
 325 \r
 326                         private ICollection collection;\r
 327                         private IEnumerator collEnum;\r
 328 \r
 329                         public PrivateICollectionEnumerator(ICollection collection, int start, int count)\r
 330                         {\r
 331                                 this.collection = collection;\r
 332                                 this.start  = start;\r
 333                                 index = -1;\r
 334                                 max = start + count;\r
 335                                 if(max > collection.Count)\r
 336                                 {\r
 337                                         max = collection.Count;\r
 338                                 }\r
 339                         }\r
 340 \r
 341                         public bool MoveNext()\r
 342                         {\r
 343                                 if(collEnum == null)\r
 344                                 {\r
 345                                         int cIndex = 0;\r
 346                                         collEnum = collection.GetEnumerator();\r
 347                                         while(cIndex < start)\r
 348                                         {\r
 349                                                 collEnum.MoveNext();\r
 350                                         }\r
 351                                 }\r
 352                                 collEnum.MoveNext();\r
 353                                 index++;\r
 354                                 return (start + index < max);\r
 355                         }\r
 356 \r
 357                         public void Reset()\r
 358                         {\r
 359                                 index = -1;\r
 360                                 collEnum = null;\r
 361                         }\r
 362 \r
 363                         public object Current\r
 364                         {\r
 365                                 get\r
 366                                 {\r
 367                                         return collEnum.Current;\r
 368                                 }\r
 369                         }\r
 370                 }\r
 371 \r
 372                 class PrivateArrayEnumerator : IEnumerator\r
 373                 {\r
 374                         private int index;\r
 375                         private int start;\r
 376                         private int max;\r
 377                         private object[] values;\r
 378 \r
 379                         public PrivateArrayEnumerator(object[] values, int start, int count)\r
 380                         {\r
 381                                 this.values = values;\r
 382                                 this.start  = start;\r
 383                                 index = -1;\r
 384                                 max = start + count;\r
 385                                 if(max > this.values.Length)\r
 386                                 {\r
 387                                         max = this.values.Length;\r
 388                                 }\r
 389                         }\r
 390 \r
 391                         public bool MoveNext()\r
 392                         {\r
 393                                 index++;\r
 394                                 return (index + start < max);\r
 395                         }\r
 396 \r
 397                         public void Reset()\r
 398                         {\r
 399                                 index = -1;\r
 400                         }\r
 401 \r
 402                         public object Current\r
 403                         {\r
 404                                 get\r
 405                                 {\r
 406                                         if(index >= 0)\r
 407                                         {\r
 408                                                 return values[index + start];\r
 409                                         }\r
 410                                         throw new InvalidOperationException("Enumerator_MoveNext_Not_Called");\r
 411                                 }\r
 412                         }\r
 413                 }\r
 414 \r
 415                 class PrivateListEnumerator : IEnumerator\r
 416                 {\r
 417                         private int   index;\r
 418                         private int   start;\r
 419                         private int   max;\r
 420                         private IList collection;\r
 421 \r
 422                         public PrivateListEnumerator(IList list, int start, int count)\r
 423                         {\r
 424                                 collection = list;\r
 425                                 this.start = start;\r
 426                                 index = -1;\r
 427                                 max = start + count;\r
 428                                 if(max > list.Count)\r
 429                                 {\r
 430                                         max = list.Count;\r
 431                                 }\r
 432                         }\r
 433 \r
 434                         public bool MoveNext()\r
 435                         {\r
 436                                 index++;\r
 437                                 return (index + start < max);\r
 438                         }\r
 439 \r
 440                         public void Reset()\r
 441                         {\r
 442                                 index = -1;\r
 443                         }\r
 444 \r
 445                         public object Current\r
 446                         {\r
 447                                 get\r
 448                                 {\r
 449                                         if(index >= 0)\r
 450                                         {\r
 451                                                 return collection[index + start];\r
 452                                         }\r
 453                                         throw new InvalidOperationException("Enumerator_MoveNext_Not_Called");\r
 454                                 }\r
 455                         }\r
 456                 }\r
 457 \r
 458                 public string GetListName(PropertyDescriptor[] listAccessors)\r
 459                 {\r
 460                         return String.Empty;\r
 461                 }\r
 462 \r
 463                 public PropertyDescriptorCollection GetItemProperties(PropertyDescriptor[] listAccessors)\r
 464                 {\r
 465                         if(dataSource != null)\r
 466                         {\r
 467                                 if(dataSource is ITypedList)\r
 468                                 {\r
 469                                         return ((ITypedList)dataSource).GetItemProperties(listAccessors);\r
 470                                 }\r
 471                         }\r
 472                         return null;\r
 473                 }\r
 474         }\r
 475 }\r