mcs/class/System.Web/System.Web.UI.HtmlControls/HtmlHead.cs

   1 //
   2 // System.Web.UI.HtmlControls.HtmlHead
   3 //
   4 // Authors:
   5 //      Lluis Sanchez Gual (lluis@novell.com)
   6 //
   7 // Copyright (C) 2004-2010 Novell, Inc (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System.ComponentModel;
  30 using System.Collections;
  31 using System.Security.Permissions;
  32 using System.Web.UI.WebControls;
  33
  34 namespace System.Web.UI.HtmlControls
  35 {
  36         // CAS - no InheritanceDemand here as the class is sealed
  37         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  38         // attributes
  39         [ControlBuilder (typeof(HtmlHeadBuilder))]
  40         public sealed class HtmlHead: HtmlGenericControl, IParserAccessor
  41         {
  42 #if NET_4_0
  43                 string descriptionText;
  44                 string keywordsText;
  45                 HtmlMeta descriptionMeta;
  46                 HtmlMeta keywordsMeta;
  47 #endif
  48                 string titleText;
  49                 HtmlTitle title;
  50                 //Hashtable metadata;
  51                 StyleSheetBag styleSheet;
  52
  53                 public HtmlHead(): base("head") {}
  54
  55                 public HtmlHead (string tag) : base (tag)
  56                 {
  57                 }
  58
  59                 protected internal override void OnInit (EventArgs e)
  60                 {
  61                         base.OnInit (e);
  62                         Page page = Page;
  63
  64                         if (page == null)
  65                                 throw new HttpException ("The <head runat=\"server\"> control requires a page.");
  66
  67                         //You can only have one <head runat="server"> control on a page.
  68                         if(page.Header != null)
  69                                 throw new HttpException ("You can only have one <head runat=\"server\"> control on a page.");
  70                         page.SetHeader (this);
  71                 }
  72
  73                 protected internal override void RenderChildren (HtmlTextWriter writer)
  74                 {
  75                         EnsureTitleControl ();
  76
  77                         base.RenderChildren (writer);
  78 //                      if (metadata != null) {
  79 //                              foreach (DictionaryEntry entry in metadata) {
  80 //                                      writer.AddAttribute ("name", entry.Key.ToString ());
  81 //                                      writer.AddAttribute ("content", entry.Value.ToString ());
  82 //                                      writer.RenderBeginTag (HtmlTextWriterTag.Meta);
  83 //                                      writer.RenderEndTag ();
  84 //                              }
  85 //                      }
  86
  87                         if (styleSheet != null)
  88                                 styleSheet.Render (writer);
  89                 }
  90
  91                 protected internal override void AddedControl (Control control, int index)
  92                 {
  93                         //You can only have one <title> element within the <head> element.
  94                         HtmlTitle t = control as HtmlTitle;
  95                         if (t != null) {
  96                                 if (title != null)
  97                                         throw new HttpException ("You can only have one <title> element within the <head> element.");
  98                                 title = t;
  99                         }
 100
 101 #if NET_4_0
 102                         HtmlMeta meta = control as HtmlMeta;
 103                         if (meta != null) {
 104                                 if (String.Compare ("keywords", meta.Name, StringComparison.OrdinalIgnoreCase) == 0)
 105                                         keywordsMeta = meta;
 106                                 else if (String.Compare ("description", meta.Name, StringComparison.OrdinalIgnoreCase) == 0)
 107                                         descriptionMeta = meta;
 108                         }
 109 #endif
 110                         base.AddedControl (control, index);
 111                 }
 112
 113                 protected internal override void RemovedControl (Control control)
 114                 {
 115                         if (title == control)
 116                                 title = null;
 117
 118 #if NET_4_0
 119                         if (keywordsMeta == control)
 120                                 keywordsMeta = null;
 121                         else if (descriptionMeta == control)
 122                                 descriptionMeta = null;
 123 #endif
 124                         base.RemovedControl (control);
 125                 }
 126
 127                 void EnsureTitleControl () {
 128                         if (title != null)
 129                                 return;
 130
 131                         HtmlTitle t = new HtmlTitle ();
 132                         t.Text = titleText;
 133                         Controls.Add (t);
 134                 }
 135
 136 //              IList LinkedStyleSheets {
 137 //                      get {
 138 //                              if (styleSheets == null) styleSheets = new ArrayList ();
 139 //                              return styleSheets;
 140 //                      }
 141 //              }
 142 //
 143 //              IDictionary Metadata {
 144 //                      get {
 145 //                              if (metadata == null) metadata = new Hashtable ();
 146 //                              return metadata;
 147 //                      }
 148 //              }
 149
 150 #if NET_4_0
 151                 public string Description {
 152                         get {
 153                                 if (descriptionMeta != null)
 154                                         return descriptionMeta.Content;
 155                                 return descriptionText;
 156                         }
 157
 158                         set {
 159                                 if (descriptionMeta != null)
 160                                         descriptionMeta.Content = value;
 161                                 else
 162                                         descriptionText = value;
 163                         }
 164                 }
 165
 166                 public string Keywords {
 167                         get {
 168                                 if (keywordsMeta != null)
 169                                         return keywordsMeta.Content;
 170                                 return keywordsText;
 171                         }
 172
 173                         set {
 174                                 if (keywordsMeta != null)
 175                                         keywordsMeta.Content = value;
 176                                 else
 177                                         keywordsText = value;
 178                         }
 179                 }
 180 #endif
 181
 182                 public IStyleSheet StyleSheet {
 183                         get {
 184                                 if (styleSheet == null) styleSheet = new StyleSheetBag ();
 185                                 return styleSheet;
 186                         }
 187                 }
 188
 189                 public string Title {
 190                         get {
 191                                 if (title != null)
 192                                         return title.Text;
 193                                 else
 194                                         return titleText;
 195                         }
 196                         set {
 197                                 if (title != null)
 198                                         title.Text = value;
 199                                 else
 200                                         titleText = value;
 201                         }
 202                 }
 203         }
 204
 205         internal class StyleSheetBag: IStyleSheet
 206         {
 207                 ArrayList entries = new ArrayList ();
 208
 209                 internal class StyleEntry
 210                 {
 211                         public Style Style;
 212                         public string Selection;
 213                         public IUrlResolutionService UrlResolver;
 214                 }
 215
 216                 public StyleSheetBag ()
 217                 {
 218                 }
 219
 220                 public void CreateStyleRule (Style style, IUrlResolutionService urlResolver, string selection)
 221                 {
 222                         StyleEntry entry = new StyleEntry ();
 223                         entry.Style = style;
 224                         entry.UrlResolver = urlResolver;
 225                         entry.Selection = selection;
 226                         entries.Add (entry);
 227                 }
 228
 229                 public void RegisterStyle (Style style, IUrlResolutionService urlResolver)
 230                 {
 231                         for (int n=0; n<entries.Count; n++) {
 232                                 if (((StyleEntry)entries[n]).Style == style)
 233                                         return;
 234                         }
 235
 236                         string name = "aspnet_" + entries.Count;
 237                         style.SetRegisteredCssClass (name);
 238                         CreateStyleRule (style, urlResolver, "." + name);
 239                 }
 240
 241                 public void Render (HtmlTextWriter writer)
 242                 {
 243                         writer.AddAttribute ("type", "text/css", false);
 244                         writer.RenderBeginTag (HtmlTextWriterTag.Style);
 245
 246                         foreach (StyleEntry entry in entries) {
 247                                 CssStyleCollection sts = entry.Style.GetStyleAttributes (entry.UrlResolver);
 248                                 writer.Write ("\n" + entry.Selection + " {" + sts.Value + "}");
 249                         }
 250
 251                         writer.RenderEndTag ();
 252                 }
 253         }
 254 }
 255