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

   1 /**\r
   2  * Namespace: System.Web.UI.WebControls\r
   3  * Class:     CheckBox\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  * Thanks to Leen Toelen (toelen@hotmail.com)'s classes that helped me\r
  13  * to write the contents of the function LoadPostData(...)\r
  14  */\r
  15 \r
  16 using System;\r
  17 using System.Collections;\r
  18 using System.Collections.Specialized;\r
  19 using System.Globalization;\r
  20 using System.Web;\r
  21 using System.Web.UI;\r
  22 \r
  23 namespace System.Web.UI.WebControls\r
  24 {\r
  25         public class CheckBox : WebControl, IPostBackDataHandler\r
  26         {\r
  27                 private static readonly object CheckedChangedEvent = new object();\r
  28                 \r
  29                 public CheckBox(): base(HtmlTextWriterTag.Input)\r
  30                 {\r
  31                 }\r
  32                 \r
  33                 public virtual bool AutoPostBack\r
  34                 {\r
  35                         get\r
  36                         {\r
  37                                 object o = ViewState["AutoPostBack"];\r
  38                                 if(o!=null)\r
  39                                         return (bool)AutoPostBack;\r
  40                                 return false;\r
  41                         }\r
  42                         set\r
  43                         {\r
  44                                 ViewState["AutoPostBack"] = value;\r
  45                         }\r
  46                 }\r
  47                 \r
  48                 public virtual bool Checked\r
  49                 {\r
  50                         get\r
  51                         {\r
  52                                 object o = ViewState["Checked"];\r
  53                                 if(o!=null)\r
  54                                         return (bool)o;\r
  55                                 return false;\r
  56                         }\r
  57                         set\r
  58                         {\r
  59                                 ViewState["Checked"] = value;\r
  60                         }\r
  61                 }\r
  62                 \r
  63                 public virtual string Text\r
  64                 {\r
  65                         get\r
  66                         {\r
  67                                 object o = ViewState["Text"];\r
  68                                 if(o!=null)\r
  69                                         return (string)o;\r
  70                                 return String.Empty;\r
  71                         }\r
  72                         set\r
  73                         {\r
  74                                 ViewState["Text"] = value;\r
  75                         }\r
  76                 }\r
  77                 \r
  78                 private bool SaveCheckedViewState\r
  79                 {\r
  80                         get\r
  81                         {\r
  82                                 if(Events[CheckedChangedEvent] != null)\r
  83                                 {\r
  84                                         if(!Enabled)\r
  85                                                 return true;\r
  86                                         if(GetType() == typeof(CheckBox))\r
  87                                         {\r
  88                                                 return false;\r
  89                                         }\r
  90                                         if(GetType() == typeof(RadioButton))\r
  91                                         {\r
  92                                                 return false;\r
  93                                         }\r
  94                                 }\r
  95                                 return true;\r
  96                                 \r
  97                         }\r
  98                 }\r
  99                 \r
 100                 public virtual TextAlign TextAlign\r
 101                 {\r
 102                         get\r
 103                         {\r
 104                                 object o = ViewState["TextAlign"];\r
 105                                 if(o!=null)\r
 106                                         return (TextAlign)o;\r
 107                                 return TextAlign.Right;\r
 108                         }\r
 109                         set\r
 110                         {\r
 111                                 if(!System.Enum.IsDefined(typeof(TextAlign), value))\r
 112                                         throw new ArgumentException();\r
 113                                 ViewState["TextAlign"] = value;\r
 114                         }\r
 115                 }\r
 116                 \r
 117                 public event EventHandler CheckedChanged\r
 118                 {\r
 119                         add\r
 120                         {\r
 121                                 Events.AddHandler(CheckedChangedEvent, value);\r
 122                         }\r
 123                         remove\r
 124                         {\r
 125                                 Events.RemoveHandler(CheckedChangedEvent, value);\r
 126                         }\r
 127                 }\r
 128                 \r
 129                 protected virtual void OnCheckedChanged(EventArgs e)\r
 130                 {\r
 131                         if(Events!=null)\r
 132                         {\r
 133                                 EventHandler eh = (EventHandler)(Events[CheckedChangedEvent]);\r
 134                                 if(eh!=null)\r
 135                                         eh(this, e);\r
 136                         }\r
 137                 }\r
 138                 \r
 139                 protected override void OnPreRender(EventArgs e)\r
 140                 {\r
 141                         if(Page!=null)\r
 142                         {\r
 143                                 if(Enabled)\r
 144                                 {\r
 145                                         Page.RegisterRequiresPostBack(this);\r
 146                                 }\r
 147                         }\r
 148                         if(SaveCheckedViewState)\r
 149                         {\r
 150                                 ViewState.SetItemDirty("checked", false);\r
 151                         }\r
 152                 }\r
 153                 \r
 154                 protected override void Render(HtmlTextWriter writer)\r
 155                 {\r
 156                         bool hasBeginRendering = false;\r
 157                         if(ControlStyleCreated)\r
 158                                 {\r
 159                                         //TODO: Uncomment this in final version\r
 160                                         /*\r
 161                                         if(!ControlStyle.IsEmpty)\r
 162                                                 {\r
 163                                                         hasBeginRendering = true;\r
 164                                                         ControlStyle.AddAttributesToRender(writer, this);\r
 165                                                 }\r
 166                                                 */\r
 167                                 }\r
 168                                 if(!Enabled)\r
 169                                         {\r
 170                                                 hasBeginRendering = true;\r
 171                                                 writer.AddAttribute(HtmlTextWriterAttribute.Disabled, "disabled");\r
 172                                         }\r
 173                                         if(ToolTip.Length > 0)\r
 174                                                 {\r
 175                                                         hasBeginRendering = true;\r
 176                                                         writer.AddAttribute(HtmlTextWriterAttribute.Title, ToolTip);\r
 177                                                 }\r
 178                                                 if(Attributes.Count > 0)\r
 179                                                         {\r
 180                                                                 hasBeginRendering = true;\r
 181                                                                 Attributes.AddAttributes(writer);\r
 182                                                         }\r
 183                                                         if(hasBeginRendering)\r
 184                                                                 writer.RenderBeginTag(HtmlTextWriterTag.Span);\r
 185                         if(Text.Length > 0)\r
 186                                 {\r
 187                                         if(TextAlign == TextAlign.Right)\r
 188                                                 {\r
 189                                                         writer.AddAttribute(HtmlTextWriterAttribute.For, ClientID);\r
 190                                                         writer.RenderBeginTag(HtmlTextWriterTag.Label);\r
 191                                                         writer.Write(Text);\r
 192                                                         writer.RenderEndTag();\r
 193                                                         RenderInputTag(writer, ClientID);\r
 194                                                 } else\r
 195                                                         {\r
 196                                                                 RenderInputTag(writer, ClientID);\r
 197                                                                 writer.AddAttribute(HtmlTextWriterAttribute.For, ClientID);\r
 198                                                                 writer.RenderBeginTag(HtmlTextWriterTag.Label);\r
 199                                                                 writer.Write(Text);\r
 200                                                         }\r
 201                                 }\r
 202                                 if(hasBeginRendering)\r
 203                                         writer.RenderEndTag();\r
 204                         throw new NotImplementedException("Calling some internal functions");\r
 205                 }\r
 206                 \r
 207                 internal virtual void RenderInputTag(HtmlTextWriter writer, string clientId)\r
 208                 {\r
 209                         writer.AddAttribute(HtmlTextWriterAttribute.Id, clientId);\r
 210                         writer.AddAttribute(HtmlTextWriterAttribute.Type, "checkbox");\r
 211                         writer.AddAttribute(HtmlTextWriterAttribute.Name, UniqueID);\r
 212                         if(Checked)\r
 213                                 {\r
 214                                         writer.AddAttribute(HtmlTextWriterAttribute.Checked, "checked");\r
 215                                 }\r
 216                                 if(AutoPostBack)\r
 217                                         {\r
 218                                                 writer.AddAttribute(HtmlTextWriterAttribute.Onclick,Page.GetPostBackClientEvent(this, String.Empty));\r
 219                                                 writer.AddAttribute("language", "javascript");\r
 220                                         }\r
 221                                         if(AccessKey.Length > 0)\r
 222                                                 {\r
 223                                                         writer.AddAttribute(HtmlTextWriterAttribute.Accesskey, AccessKey);\r
 224                                                 }\r
 225                                                 if(TabIndex != 0)\r
 226                                                         {\r
 227                                                                 writer.AddAttribute(HtmlTextWriterAttribute.Tabindex, TabIndex.ToString(NumberFormatInfo.InvariantInfo));\r
 228                                                         }\r
 229                                                         writer.RenderBeginTag(HtmlTextWriterTag.Input);\r
 230                         writer.RenderEndTag();\r
 231                 }\r
 232                 \r
 233                 bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection)\r
 234                 {\r
 235                         string postedVal = postCollection[postDataKey];\r
 236                         bool   postChecked = false;\r
 237                         if(postedVal != null)\r
 238                                 {\r
 239                                         postChecked = postedVal.Length > 0;\r
 240                                 }\r
 241                                 Checked = postChecked;\r
 242                         return (postChecked == Checked == false);\r
 243                 }\r
 244                 \r
 245                 void IPostBackDataHandler.RaisePostDataChangedEvent()\r
 246                 {\r
 247                         OnCheckedChanged(EventArgs.Empty);\r
 248                 }\r
 249         }\r
 250 }\r