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

   1 /**\r
   2  * Namespace: System.Web.UI.WebControls\r
   3  * Class:     ListControl\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 (2001)\r
  12  */\r
  13 \r
  14 using System;\r
  15 using System.Collections;\r
  16 using System.ComponentModel;\r
  17 using System.Web;\r
  18 using System.Web.UI;\r
  19 using System.Web.Util;\r
  20 \r
  21 namespace System.Web.UI.WebControls\r
  22 {\r
  23         [DefaultEvent("SelectedIndexChanged")]\r
  24         [DefaultProperty("DataSource")]\r
  25         //[Designer("??")]\r
  26         //[DataBindingHandler("??")]\r
  27         [ParseChildren(true, "Items")]\r
  28         public abstract class ListControl: WebControl\r
  29         {\r
  30                 private static readonly object SelectedIndexChangedEvent = new object();\r
  31 \r
  32                 private object             dataSource;\r
  33                 private ListItemCollection items;\r
  34 \r
  35                 private int cachedSelectedIndex = -1;\r
  36 \r
  37                 public ListControl(): base(HtmlTextWriterTag.Select)\r
  38                 {\r
  39                 }\r
  40 \r
  41                 public event EventHandler SelectedIndexChanged\r
  42                 {\r
  43                         add\r
  44                         {\r
  45                                 Events.AddHandler(SelectedIndexChangedEvent, value);\r
  46                         }\r
  47                         remove\r
  48                         {\r
  49                                 Events.RemoveHandler(SelectedIndexChangedEvent, value);\r
  50                         }\r
  51                 }\r
  52 \r
  53                 public virtual bool AutoPostBack\r
  54                 {\r
  55                         get\r
  56                         {\r
  57                                 object o = ViewState["AutoPostBack"];\r
  58                                 if(o!=null)\r
  59                                         return (bool)o;\r
  60                                 return false;\r
  61                         }\r
  62                         set\r
  63                         {\r
  64                                 ViewState["AutoPostBack"] = value;\r
  65                         }\r
  66                 }\r
  67 \r
  68                 public virtual string DataMember\r
  69                 {\r
  70                         get\r
  71                         {\r
  72                                 object o = ViewState["DataMember"];\r
  73                                 if(o!=null)\r
  74                                         return (string)o;\r
  75                                 return String.Empty;\r
  76                         }\r
  77                         set\r
  78                         {\r
  79                                 ViewState["DataMember"] = value;\r
  80                         }\r
  81                 }\r
  82 \r
  83                 public virtual object DataSource\r
  84                 {\r
  85                         get\r
  86                         {\r
  87                                 return dataSource;\r
  88                         }\r
  89                         set\r
  90                         {\r
  91                                 if(value != null)\r
  92                                 {\r
  93                                         if(value is IListSource || value is IEnumerable)\r
  94                                         {\r
  95                                                 dataSource = value;\r
  96                                                 return;\r
  97                                         }\r
  98                                 }\r
  99                                 throw new ArgumentException(HttpRuntime.FormatResourceString(ID, "Invalid DataSource Type"));\r
 100                         }\r
 101                 }\r
 102 \r
 103                 public virtual string DataTextField\r
 104                 {\r
 105                         get\r
 106                         {\r
 107                                 object o = ViewState["DataTextField"];\r
 108                                 if(o!=null)\r
 109                                         return (string)o;\r
 110                                 return String.Empty;\r
 111                         }\r
 112                         set\r
 113                         {\r
 114                                 ViewState["DataTextField"] = value;\r
 115                         }\r
 116                 }\r
 117 \r
 118                 public virtual string DataTextFormatString\r
 119                 {\r
 120                         get\r
 121                         {\r
 122                                 object o = ViewState["DataTextFormatString"];\r
 123                                 if(o!=null)\r
 124                                         return (string)o;\r
 125                                 return String.Empty;\r
 126                         }\r
 127                         set\r
 128                         {\r
 129                                 ViewState["DataTextFormatString"] = value;\r
 130                         }\r
 131                 }\r
 132 \r
 133                 public virtual string DataValueField\r
 134                 {\r
 135                         get\r
 136                         {\r
 137                                 object o = ViewState["DataValueField"];\r
 138                                 if(o!=null)\r
 139                                         return (string)o;\r
 140                                 return String.Empty;\r
 141                         }\r
 142                         set\r
 143                         {\r
 144                                 ViewState["DataValueField"] = value;\r
 145                         }\r
 146                 }\r
 147 \r
 148                 public virtual ListItemCollection Items\r
 149                 {\r
 150                         get\r
 151                         {\r
 152                                 if(items==null)\r
 153                                 {\r
 154                                         items = new ListItemCollection();\r
 155                                         if(IsTrackingViewState)\r
 156                                         {\r
 157                                                 items.TrackViewState();\r
 158                                         }\r
 159                                 }\r
 160                                 return items;\r
 161                         }\r
 162                 }\r
 163 \r
 164                 public virtual int SelectedIndex\r
 165                 {\r
 166                         get {\r
 167                                 ListItemCollection items = Items;\r
 168                                 int last = items.Count;\r
 169                                 for (int i = 0; i < last; i++) {\r
 170                                         if (items [i].Selected)\r
 171                                                 return i;\r
 172                                 }\r
 173                                 return -1;\r
 174                         }\r
 175                         set {\r
 176                                 if (value < -1 || value > Items.Count)\r
 177                                         throw new ArgumentOutOfRangeException ();\r
 178 \r
 179                                 ClearSelection ();\r
 180                                 if (value != -1)\r
 181                                         Items [value].Selected = true;\r
 182                         }\r
 183                 }\r
 184 \r
 185                 public virtual ListItem SelectedItem\r
 186                 {\r
 187                         get\r
 188                         {\r
 189                                 int idx = SelectedIndex;\r
 190                                 if (idx < 0)\r
 191                                         return null;\r
 192 \r
 193                                 return Items [idx];\r
 194                         }\r
 195                 }\r
 196 \r
 197                 internal virtual ArrayList SelectedIndices\r
 198                 {\r
 199                         get\r
 200                         {\r
 201                                 ArrayList si = new ArrayList();\r
 202                                 for(int i=0; i < Items.Count; i++)\r
 203                                 {\r
 204                                         if(Items[i].Selected)\r
 205                                                 si.Add(i);\r
 206                                 }\r
 207                                 return si;\r
 208                         }\r
 209                 }\r
 210 \r
 211                 internal void Select(ArrayList indices)\r
 212                 {\r
 213                         ClearSelection();\r
 214                         foreach(object intObj in indices)\r
 215                         {\r
 216                                 int index = (int)intObj;\r
 217                                 if(index >= 0 && index < Items.Count)\r
 218                                         Items[index].Selected = true;\r
 219                         }\r
 220                 }\r
 221 \r
 222                 public virtual void ClearSelection()\r
 223                 {\r
 224                         for(int i=0; i < Items.Count; i++)\r
 225                         {\r
 226                                 Items[i].Selected = false;\r
 227                         }\r
 228                 }\r
 229 \r
 230                 protected override void LoadViewState(object savedState)\r
 231                 {\r
 232                         //Order: BaseClass, Items (Collection), Indices\r
 233                         if(savedState != null && savedState is Triplet)\r
 234                         {\r
 235                                 Triplet state = (Triplet)savedState;\r
 236                                 base.LoadViewState(state.First);\r
 237                                 Items.LoadViewState(state.Second);\r
 238                                 object indices = state.Third;\r
 239                                 if(indices != null)\r
 240                                 {\r
 241                                         Select((ArrayList)indices);\r
 242                                 }\r
 243                         }\r
 244                 }\r
 245 \r
 246                 protected override void OnDataBinding(EventArgs e)\r
 247                 {\r
 248                         base.OnDataBinding(e);\r
 249                         IEnumerable ds = DataSourceHelper.GetResolvedDataSource (DataSource, DataMember);\r
 250 \r
 251                         if(ds != null) {\r
 252                                 string dtf = DataTextField;\r
 253                                 string dvf = DataValueField;\r
 254                                 string dtfs = DataTextFormatString;\r
 255                                 if (dtfs.Length == 0)\r
 256                                         dtfs = "{0}";\r
 257 \r
 258                                 Items.Clear();\r
 259 \r
 260                                 bool useProperties = (dtf.Length > 0 && dvf.Length > 0);\r
 261 \r
 262                                 foreach (object current in ds) {\r
 263                                         ListItem li = new ListItem();\r
 264                                         if (!useProperties){\r
 265                                                 li.Text  = String.Format (dtfs, current);\r
 266                                                 li.Value = current.ToString ();\r
 267                                                 Items.Add (li);\r
 268                                                 continue;\r
 269                                         }\r
 270 \r
 271                                         object o;\r
 272                                         if (dtf.Length > 0) {\r
 273                                                 o = DataBinder.GetPropertyValue (current, dtf, null);\r
 274                                                 li.Text = o.ToString ();\r
 275                                         }\r
 276 \r
 277                                         if (dvf.Length > 0) {\r
 278                                                 o = DataBinder.GetPropertyValue (current, dvf, null);\r
 279                                                 li.Value = o.ToString ();\r
 280                                         }\r
 281 \r
 282                                         Items.Add(li);\r
 283                                 }\r
 284                         }\r
 285 \r
 286                         if (cachedSelectedIndex != -1) {\r
 287                                 SelectedIndex = cachedSelectedIndex;\r
 288                                 cachedSelectedIndex = -1;\r
 289                         }\r
 290                 }\r
 291 \r
 292                 protected virtual void OnSelectedIndexChanged(EventArgs e)\r
 293                 {\r
 294                         if(Events!=null)\r
 295                                 {\r
 296                                         EventHandler eh = (EventHandler)(Events[SelectedIndexChangedEvent]);\r
 297                                         if(eh!=null)\r
 298                                                 eh(this, e);\r
 299                                 }\r
 300                 }\r
 301 \r
 302                 protected override void OnPreRender (EventArgs e)\r
 303                 {\r
 304                         base.OnPreRender(e);\r
 305                 }\r
 306 \r
 307                 protected override object SaveViewState()\r
 308                 {\r
 309                         //Order: BaseClass, Items (Collection), Indices\r
 310                         object vs = base.SaveViewState();\r
 311                         object itemSvs = Items.SaveViewState();\r
 312                         object indices = null;\r
 313                         if(SaveSelectedIndicesViewState)\r
 314                                 indices = SelectedIndices;\r
 315                         if(vs!= null && itemSvs != null && indices != null)\r
 316                         {\r
 317                                 return new Triplet(vs, itemSvs, indices);\r
 318                         }\r
 319                         return null;\r
 320                 }\r
 321 \r
 322                 protected override void TrackViewState()\r
 323                 {\r
 324                         base.TrackViewState();\r
 325                         Items.TrackViewState();\r
 326                 }\r
 327 \r
 328                 private bool SaveSelectedIndicesViewState\r
 329                 {\r
 330                         get\r
 331                         {\r
 332                                 if( Events[SelectedIndexChangedEvent] != null && Enabled && Visible)\r
 333                                 {\r
 334                                         Type t = GetType();\r
 335                                         // If I am a derivative, let it take of storing the selected indices.\r
 336                                         if(t == typeof(DropDownList) || t == typeof(ListBox) || t == typeof(CheckBoxList) || t == typeof(RadioButtonList))\r
 337                                                 return false;\r
 338                                 }\r
 339                                 return true;\r
 340                         }\r
 341                 }\r
 342         }\r
 343 }\r