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  * Status:  60%\r
   9  * \r
  10  * (C) Gaurav Vaish (2001)\r
  11  * Thanks to Leen Toelen (toelen@hotmail.com)'s classes that helped me\r
  12  * to write the contents of the function LoadPostData(...)\r
  13  */\r
  14 \r
  15 using System;\r
  16 using System.Collections;\r
  17 using System.Collections.Specialized;\r
  18 using System.Web;\r
  19 using System.Web.UI;\r
  20 \r
  21 namespace System.Web.UI.WebControls\r
  22 {\r
  23         public class CheckBox : WebControl, IPostBackDataHandler\r
  24         {\r
  25                 private static readonly object CheckedChangedEvent = new object();\r
  26 \r
  27                 public CheckBox()\r
  28                 {\r
  29                         //\r
  30                 }\r
  31                 \r
  32                 public virtual bool AutoPostBack\r
  33                 {\r
  34                         get\r
  35                         {\r
  36                                 object o = ViewState["AutoPostBack"];\r
  37                                 if(o!=null)\r
  38                                         return (bool)AutoPostBack;\r
  39                                 return false;\r
  40                         }\r
  41                         set\r
  42                         {\r
  43                                 ViewState["AutoPostBack"] = value;\r
  44                         }\r
  45                 }\r
  46                 \r
  47                 public virtual bool Checked\r
  48                 {\r
  49                         get\r
  50                         {\r
  51                                 object o = ViewState["Checked"];\r
  52                                 if(o!=null)\r
  53                                         return (bool)o;\r
  54                                 return false;\r
  55                         }\r
  56                         set\r
  57                         {\r
  58                                 ViewState["Checked"] = value;\r
  59                         }\r
  60                 }\r
  61 \r
  62                 public virtual string Text\r
  63                 {\r
  64                         get\r
  65                         {\r
  66                                 object o = ViewState["Text"];\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["Text"] = value;\r
  74                         }\r
  75                 }\r
  76                 \r
  77                 public virtual TextAlign TextAlign\r
  78                 {\r
  79                         get\r
  80                         {\r
  81                                 object o = ViewState["TextAlign"];\r
  82                                 if(o!=null)\r
  83                                         return (TextAlign)o;\r
  84                                 return TextAlign.Right;\r
  85                         }\r
  86                         set\r
  87                         {\r
  88                                 if(!System.Enum.IsDefined(typeof(TextAlign), value))\r
  89                                         throw new ArgumentException();\r
  90                                 ViewState["TextAlign"] = value;\r
  91                         }\r
  92                 }\r
  93                 \r
  94                 public event EventHandler CheckedChanged\r
  95                 {\r
  96                         add\r
  97                         {\r
  98                                 Events.AddHandler(CheckedChangedEvent, value);\r
  99                         }\r
 100                         remove\r
 101                         {\r
 102                                 Events.RemoveHandler(CheckedChangedEvent, value);\r
 103                         }\r
 104                 }\r
 105                 \r
 106                 protected virtual void OnCheckedChanged(EventArgs e)\r
 107                 {\r
 108                         if(Events!=null)\r
 109                         {\r
 110                                 EventHandler eh = (EventHandler)(Events[CheckedChangedEvent]);\r
 111                                 if(eh!=null)\r
 112                                         eh(this, e);\r
 113                         }\r
 114                 }\r
 115                 \r
 116                 protected virtual void OnPreRender(EventArgs e)\r
 117                 {\r
 118                         throw new NotImplementedException();\r
 119                 }\r
 120                 \r
 121                 protected override void Render(HtmlTextWriter writer)\r
 122                 {\r
 123                         //TODO: THE LOST WORLD!\r
 124                         bool hasBeginRendering = false;\r
 125                         if(ControlStyleCreated)\r
 126                         {\r
 127                                 if(!ControlStyle.IsEmpty)\r
 128                                 {\r
 129                                         hasBeginRendering = true;\r
 130                                         ControlStyle.AddAttributesToRender(writer, this);\r
 131                                 }\r
 132                         }\r
 133                         if(!Enabled)\r
 134                         {\r
 135                                 hasBeginRendering = true;\r
 136                                 writer.AddAttribute(HtmlTextWriterAttribute.Disbled, "disabled");\r
 137                         }\r
 138                         if(ToolTip.Length > 0)\r
 139                         {\r
 140                                 hasBeginRendering = true;\r
 141                                 writer.AddAttribute(HtmlTextWriterAttribute.Title, ToolTip);\r
 142                         }\r
 143                         if(Attributes.Count > 0)\r
 144                         {\r
 145                                 hasBeginRendering = true;\r
 146                                 Attributes.AddAttributes(writer);\r
 147                         }\r
 148                         if(hasBeginRendering)\r
 149                                 writer.RenderBeginTag(HtmlTextWriterTag.Span);\r
 150                         if(Text.Length > 0)\r
 151                         {\r
 152                                 // Looks wierd, ain't? But found out interestingly.\r
 153                                 if(TextAlign == TextAlign.Right)\r
 154                                 {\r
 155                                         writer.AddAttribute(HtmlTextWriterAttribute.For, ClientID);\r
 156                                         writer.RenderBeginTag(HtmlTextWriterTag.Label);\r
 157                                         writer.Write(Text);\r
 158                                         writer.RenderEngTag();\r
 159                                         RenderInputTag(writer, ClientID);\r
 160                                 } else\r
 161                                 {\r
 162                                         RenderInputTag(writer, ClientID);\r
 163                                         writer.AddAttribute(HtmlTextWriterAttribute.For, ClientID);\r
 164                                         writer.RenderBeginTag(HtmlTextWriterTag.Label);\r
 165                                         writer.Write(Text);\r
 166                                 }\r
 167                         }\r
 168                         if(hasBeginRendering)\r
 169                                 writer.RenderEndTag();\r
 170                 }\r
 171                 \r
 172                 internal virtual void RenderInputTag(HtmlTextWriter writer, string clientId)\r
 173                 {\r
 174                         writer.AddAttribute(HtmlTextWriterAttribute.Id, clientId);\r
 175                         writer.AddAttribute(HtmlTextWriterAttribute.Type, "checkbox");\r
 176                         writer.AddAttribute(HtmlTextWriterAttribute.Name, UniqueID);\r
 177                         if(Checked)\r
 178                         {\r
 179                                 writer.AddAttribute(HtmlTextWriterAttribute.Checked, "checked");\r
 180                         }\r
 181                         if(AutoPostBack)\r
 182                         {\r
 183                                 writer.AddAttribute(HtmlTextWriterAttribute.OnClick,Page.GetPostBackClientEvent(this, String.Empty));\r
 184                                 writer.AddAttribute("language", "javascript");\r
 185                         }\r
 186                         if(AccessKey.Length > 0)\r
 187                         {\r
 188                                 writer.AddAttribute(HtmlTextWriterAttribute.AccessKey, AccessKey);\r
 189                         }\r
 190                         if(TabIndex != 0)\r
 191                         {\r
 192                                 writer.AddAttribute(HtmlTextWriterAttribute.TabIndex, TabIndex.ToString(NumberFormatInfo.InvariantInfo));\r
 193                         }\r
 194                         writer.RenderBeginTag(HtmlTextWriterTag.Input);\r
 195                         writer.RenderEndTag();\r
 196                 }\r
 197                 \r
 198                 public bool LoadPostData(string postDataKey, NameValueCollection postCollection)\r
 199                 {\r
 200                         string postedVal = postCollection[postDataKey];\r
 201                         bool   postChecked = false;\r
 202                         if(postedVal != null)\r
 203                         {\r
 204                                 postChecked = postedVal.Length > 0;\r
 205                         }\r
 206                         Checked = postChecked;\r
 207                         return (postChecked == Checked == false);\r
 208                 }\r
 209                 \r
 210                 public void RaisePostDataChangedEvent()\r
 211                 {\r
 212                         OnCheckedChanged(EventArgs.Empty);\r
 213                 }\r
 214         }\r
 215 }\r