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                         base.RenderChildren (writer);
  76                         if (title == null) {
  77                                 writer.RenderBeginTag (HtmlTextWriterTag.Title);
  78                                 if (!String.IsNullOrEmpty (titleText))
  79                                         writer.Write (titleText);
  80                                 writer.RenderEndTag ();
  81                         }
  82 #if NET_4_0
  83                         if (descriptionMeta == null && descriptionText != null) {
  84                                 writer.AddAttribute ("name", "description");
  85                                 writer.AddAttribute ("content", HttpUtility.HtmlAttributeEncode (descriptionText));
  86                                 writer.RenderBeginTag (HtmlTextWriterTag.Meta);
  87                                 writer.RenderEndTag ();
  88                         }
  89
  90                         if (keywordsMeta == null && keywordsText != null) {
  91                                 writer.AddAttribute ("name", "keywords");
  92                                 writer.AddAttribute ("content", HttpUtility.HtmlAttributeEncode (keywordsText));
  93                                 writer.RenderBeginTag (HtmlTextWriterTag.Meta);
  94                                 writer.RenderEndTag ();
  95                         }
  96 #endif
  97                         if (styleSheet != null)
  98                                 styleSheet.Render (writer);
  99                 }
 100
 101                 protected internal override void AddedControl (Control control, int index)
 102                 {
 103                         //You can only have one <title> element within the <head> element.
 104                         HtmlTitle t = control as HtmlTitle;
 105                         if (t != null) {
 106                                 if (title != null)
 107                                         throw new HttpException ("You can only have one <title> element within the <head> element.");
 108                                 title = t;
 109                         }
 110
 111 #if NET_4_0
 112                         HtmlMeta meta = control as HtmlMeta;
 113                         if (meta != null) {
 114                                 if (String.Compare ("keywords", meta.Name, StringComparison.OrdinalIgnoreCase) == 0)
 115                                         keywordsMeta = meta;
 116                                 else if (String.Compare ("description", meta.Name, StringComparison.OrdinalIgnoreCase) == 0)
 117                                         descriptionMeta = meta;
 118                         }
 119 #endif
 120                         base.AddedControl (control, index);
 121                 }
 122
 123                 protected internal override void RemovedControl (Control control)
 124                 {
 125                         if (title == control)
 126                                 title = null;
 127
 128 #if NET_4_0
 129                         if (keywordsMeta == control)
 130                                 keywordsMeta = null;
 131                         else if (descriptionMeta == control)
 132                                 descriptionMeta = null;
 133 #endif
 134                         base.RemovedControl (control);
 135                 }
 136 #if NET_4_0
 137                 public string Description {
 138                         get {
 139                                 if (descriptionMeta != null)
 140                                         return descriptionMeta.Content;
 141                                 return descriptionText;
 142                         }
 143
 144                         set {
 145                                 if (descriptionMeta != null)
 146                                         descriptionMeta.Content = value;
 147                                 else
 148                                         descriptionText = value;
 149                         }
 150                 }
 151
 152                 public string Keywords {
 153                         get {
 154                                 if (keywordsMeta != null)
 155                                         return keywordsMeta.Content;
 156                                 return keywordsText;
 157                         }
 158
 159                         set {
 160                                 if (keywordsMeta != null)
 161                                         keywordsMeta.Content = value;
 162                                 else
 163                                         keywordsText = value;
 164                         }
 165                 }
 166 #endif
 167
 168                 public IStyleSheet StyleSheet {
 169                         get {
 170                                 if (styleSheet == null) styleSheet = new StyleSheetBag ();
 171                                 return styleSheet;
 172                         }
 173                 }
 174
 175                 public string Title {
 176                         get {
 177                                 if (title != null)
 178                                         return title.Text;
 179                                 else
 180                                         return titleText;
 181                         }
 182                         set {
 183                                 if (title != null)
 184                                         title.Text = value;
 185                                 else
 186                                         titleText = value;
 187                         }
 188                 }
 189         }
 190
 191         internal class StyleSheetBag: IStyleSheet
 192         {
 193                 ArrayList entries = new ArrayList ();
 194
 195                 internal class StyleEntry
 196                 {
 197                         public Style Style;
 198                         public string Selection;
 199                         public IUrlResolutionService UrlResolver;
 200                 }
 201
 202                 public StyleSheetBag ()
 203                 {
 204                 }
 205
 206                 public void CreateStyleRule (Style style, IUrlResolutionService urlResolver, string selection)
 207                 {
 208                         StyleEntry entry = new StyleEntry ();
 209                         entry.Style = style;
 210                         entry.UrlResolver = urlResolver;
 211                         entry.Selection = selection;
 212                         entries.Add (entry);
 213                 }
 214
 215                 public void RegisterStyle (Style style, IUrlResolutionService urlResolver)
 216                 {
 217                         for (int n=0; n<entries.Count; n++) {
 218                                 if (((StyleEntry)entries[n]).Style == style)
 219                                         return;
 220                         }
 221
 222                         string name = "aspnet_" + entries.Count;
 223                         style.SetRegisteredCssClass (name);
 224                         CreateStyleRule (style, urlResolver, "." + name);
 225                 }
 226
 227                 public void Render (HtmlTextWriter writer)
 228                 {
 229                         writer.AddAttribute ("type", "text/css", false);
 230                         writer.RenderBeginTag (HtmlTextWriterTag.Style);
 231
 232                         foreach (StyleEntry entry in entries) {
 233                                 CssStyleCollection sts = entry.Style.GetStyleAttributes (entry.UrlResolver);
 234                                 writer.Write ("\n" + entry.Selection + " {" + sts.Value + "}");
 235                         }
 236
 237                         writer.RenderEndTag ();
 238                 }
 239         }
 240 }
 241