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