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

   1 /**\r
   2  * Namespace: System.Web.UI.WebControls\r
   3  * Class:     ListItem\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.Web;\r
  17 using System.Web.UI;\r
  18 \r
  19 namespace System.Web.UI.WebControls\r
  20 {\r
  21         public sealed class ListItem : IStateManager, IParserAccessor, IAttributeAccessor\r
  22         {\r
  23                 private static int MARKED   = (0x01 << 0);\r
  24                 private static int SELECTED = (0x01 << 1);\r
  25                 private static int DIRTY_T  = (0x01 << 2);\r
  26                 private static int DIRTY_V  = (0x01 << 3);\r
  27                 \r
  28                 private static int selBits;\r
  29                 \r
  30                 private AttributeCollection attributes;\r
  31                 private string              text;\r
  32                 private string              val;\r
  33                 \r
  34                 public ListItem(string text, string value)\r
  35                 {\r
  36                         this.text  = text;\r
  37                         this.val   = value;\r
  38                         selBits    = 0x00;\r
  39                         attributes = null;\r
  40                 }\r
  41                 \r
  42                 public ListItem(string text): this(text, null)\r
  43                 {\r
  44                 }\r
  45                 \r
  46                 public ListItem(): this(null, null)\r
  47                 {\r
  48                 }\r
  49                 \r
  50                 public static ListItem FromString(string text)\r
  51                 {\r
  52                         return new ListItem(text);\r
  53                 }\r
  54                 \r
  55                 public AttributeCollection Attributes\r
  56                 {\r
  57                         get\r
  58                         {\r
  59                                 if(attributes == null)\r
  60                                         attributes = new AttributeCollection(new StateBag(true));\r
  61                                 return attributes;\r
  62                         }\r
  63                 }\r
  64                 \r
  65                 public bool Selected\r
  66                 {\r
  67                         get\r
  68                         {\r
  69                                 return IsSet(SELECTED);\r
  70                         }\r
  71                         set\r
  72                         {\r
  73                                 Set(SELECTED);\r
  74                         }\r
  75                 }\r
  76                 \r
  77                 internal bool Dirty\r
  78                 {\r
  79                         get\r
  80                         {\r
  81                                 return (IsSet(DIRTY_T) && IsSet(DIRTY_V));\r
  82                         }\r
  83                         set\r
  84                         {\r
  85                                 Set(DIRTY_T);\r
  86                                 Set(DIRTY_V);\r
  87                         }\r
  88                 }\r
  89                 \r
  90                 private bool IsSet(int bit)\r
  91                 {\r
  92                         return ( (selBits & bit) != 0x00 );\r
  93                 }\r
  94                 \r
  95                 private void Set(int bit)\r
  96                 {\r
  97                         selBits |= bit;\r
  98                 }\r
  99                 \r
 100                 public string Text\r
 101                 {\r
 102                         get\r
 103                         {\r
 104                                 if(text!=null)\r
 105                                 {\r
 106                                         return text;\r
 107                                 }\r
 108                                 if(val!=null)\r
 109                                 {\r
 110                                         return val;\r
 111                                 }\r
 112                                 return String.Empty;\r
 113                         }\r
 114                         set\r
 115                         {\r
 116                                 text = value;\r
 117                                 if(IsTrackingViewState)\r
 118                                 {\r
 119                                         Set(DIRTY_T);\r
 120                                 }\r
 121                         }\r
 122                 }\r
 123                 \r
 124                 public string Value\r
 125                 {\r
 126                         get\r
 127                         {\r
 128                                 if(val!=null)\r
 129                                 {\r
 130                                         return val;\r
 131                                 }\r
 132                                 if(text!=null)\r
 133                                 {\r
 134                                         return text;\r
 135                                 }\r
 136                                 return String.Empty;\r
 137                         }\r
 138                         set\r
 139                         {\r
 140                                 val = value;\r
 141                                 if(IsTrackingViewState)\r
 142                                 {\r
 143                                         Set(DIRTY_V);\r
 144                                 }\r
 145                         }\r
 146                 }\r
 147                 \r
 148                 string IAttributeAccessor.GetAttribute(string key)\r
 149                 {\r
 150                         return attributes[key];\r
 151                 }\r
 152                 \r
 153                 void IAttributeAccessor.SetAttribute(string key, string value)\r
 154                 {\r
 155                         attributes[key] = value;\r
 156                 }\r
 157                 \r
 158                 /// <remarks>\r
 159                 /// The data is parsed - object must be of type LiteralControl or DataBoundLiteralControl.\r
 160                 /// In latter case, throw an exception telling that the data cannot be bind-ed.\r
 161                 /// </remarks>\r
 162                 void IParserAccessor.AddParsedSubObject(object obj)\r
 163                 {\r
 164                         if(obj is LiteralControl)\r
 165                         {\r
 166                                 Text = ((LiteralControl)obj).Text;\r
 167                                 return;\r
 168                         }\r
 169                         if(obj is DataBoundLiteralControl)\r
 170                         {\r
 171                                 throw new HttpException(HttpRuntime.FormatResourceString("Control_Cannot_DataBind","ListItem"));\r
 172                         }\r
 173                         throw new HttpException(HttpRuntime.FormatResourceString("Cannot_Have_Children_Of_Type", "ListItem", obj.GetType().ToString()));\r
 174                 }\r
 175 \r
 176                 internal bool IsTrackingViewState\r
 177                 {\r
 178                         get\r
 179                         {\r
 180                                 return IsSet(MARKED);\r
 181                         }\r
 182                 }\r
 183 \r
 184                 internal void TrackViewState()\r
 185                 {\r
 186                         Set(MARKED);\r
 187                 }\r
 188 \r
 189                 internal void LoadViewState(object state)\r
 190                 {\r
 191                         if(state is Pair)\r
 192                         {\r
 193                                 Pair tv = (Pair)state;\r
 194                                 if(tv.First!=null)\r
 195                                 {\r
 196                                         Text = (string)tv.First;\r
 197                                 }\r
 198                                 if(tv.Second!=null)\r
 199                                 {\r
 200                                         Value = (string)tv.Second;\r
 201                                 }\r
 202                         }\r
 203                         if(state is string)\r
 204                         {\r
 205                                 Text = (string)state;\r
 206                         }\r
 207                 }\r
 208 \r
 209                 internal object SaveViewState()\r
 210                 {\r
 211                         if(IsSet(DIRTY_T) && IsSet(DIRTY_V))\r
 212                         {\r
 213                                 return new Pair(Text, Value);\r
 214                         }\r
 215                         if(IsSet(DIRTY_T))\r
 216                         {\r
 217                                 return Text;\r
 218                         }\r
 219                         if(IsSet(DIRTY_V))\r
 220                         {\r
 221                                 return new Pair(null, Value);\r
 222                         }\r
 223                         return null;\r
 224                 }\r
 225                 \r
 226                 bool IStateManager.IsTrackingViewState\r
 227                 {\r
 228                         get\r
 229                         {\r
 230                                 return IsTrackingViewState;\r
 231                         }\r
 232                 }\r
 233                 \r
 234                 void IStateManager.TrackViewState()\r
 235                 {\r
 236                         TrackViewState();\r
 237                 }\r
 238                 \r
 239                 object IStateManager.SaveViewState()\r
 240                 {\r
 241                         return SaveViewState();\r
 242                 }\r
 243                 \r
 244                 void IStateManager.LoadViewState(object state)\r
 245                 {\r
 246                         LoadViewState(state);\r
 247                 }\r
 248         }\r
 249 }\r