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) 2004-2005 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 #if NET_2_0
  30
  31 using System.ComponentModel;
  32 using System.Collections;
  33 using System.Security.Permissions;
  34 using System.Web.UI.WebControls;
  35
  36 namespace System.Web.UI.HtmlControls
  37 {
  38         // CAS - no InheritanceDemand here as the class is sealed
  39         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  40         // attributes
  41         [ControlBuilder (typeof(HtmlHeadBuilder))]
  42         public sealed class HtmlHead: HtmlGenericControl, IParserAccessor {
  43
  44                 string titleText;
  45                 HtmlTitle title;
  46                 Hashtable metadata;
  47                 ArrayList styleSheets;
  48                 StyleSheetBag styleSheet;
  49
  50                 public HtmlHead(): base("head") {}
  51
  52                 public HtmlHead (string tag) : base (tag)
  53                 {
  54                 }
  55
  56                 protected internal override void OnInit (EventArgs e)
  57                 {
  58                         //You can only have one <head runat="server"> control on a page.
  59                         if(Page.Header!=null)
  60                                 throw new HttpException ("You can only have one <head runat=\"server\"> control on a page.");
  61                         Page.SetHeader (this);
  62                 }
  63
  64                 protected internal override void RenderChildren (HtmlTextWriter writer)
  65                 {
  66                         EnsureTitleControl ();
  67
  68                         base.RenderChildren (writer);
  69                         if (metadata != null) {
  70                                 foreach (DictionaryEntry entry in metadata) {
  71                                         writer.AddAttribute ("name", entry.Key.ToString ());
  72                                         writer.AddAttribute ("content", entry.Value.ToString ());
  73                                         writer.RenderBeginTag (HtmlTextWriterTag.Meta);
  74                                         writer.RenderEndTag ();
  75                                 }
  76                         }
  77
  78                         if (styleSheet != null)
  79                                 styleSheet.Render (writer);
  80                 }
  81
  82                 protected internal override void AddedControl (Control control, int index)
  83                 {
  84                         //You can only have one <title> element within the <head> element.
  85                         HtmlTitle t = control as HtmlTitle;
  86                         if (t != null) {
  87                                 if (title != null)
  88                                         throw new HttpException ("You can only have one <title> element within the <head> element.");
  89                                 title = t;
  90                         }
  91
  92                         base.AddedControl (control, index);
  93                 }
  94
  95                 protected internal override void RemovedControl (Control control)
  96                 {
  97                         if (title == control)
  98                                 title = null;
  99
 100                         base.RemovedControl (control);
 101                 }
 102
 103                 void EnsureTitleControl () {
 104                         if (title != null)
 105                                 return;
 106
 107                         HtmlTitle t = new HtmlTitle ();
 108                         t.Text = titleText;
 109                         Controls.Add (t);
 110                 }
 111
 112                 IList LinkedStyleSheets {
 113                         get {
 114                                 if (styleSheets == null) styleSheets = new ArrayList ();
 115                                 return styleSheets;
 116                         }
 117                 }
 118
 119                 IDictionary Metadata {
 120                         get {
 121                                 if (metadata == null) metadata = new Hashtable ();
 122                                 return metadata;
 123                         }
 124                 }
 125
 126                 public IStyleSheet StyleSheet {
 127                         get {
 128                                 if (styleSheet == null) styleSheet = new StyleSheetBag ();
 129                                 return styleSheet;
 130                         }
 131                 }
 132
 133                 public string Title {
 134                         get {
 135                                 if (title != null)
 136                                         return title.Text;
 137                                 else
 138                                         return titleText;
 139                         }
 140                         set {
 141                                 if (title != null)
 142                                         title.Text = value;
 143                                 else
 144                                         titleText = value;
 145                         }
 146                 }
 147         }
 148
 149         internal class StyleSheetBag: IStyleSheet
 150         {
 151                 ArrayList entries = new ArrayList ();
 152
 153                 internal class StyleEntry
 154                 {
 155                         public Style Style;
 156                         public string Selection;
 157                         public IUrlResolutionService UrlResolver;
 158                 }
 159
 160                 public StyleSheetBag ()
 161                 {
 162                 }
 163
 164                 public void CreateStyleRule (Style style, IUrlResolutionService urlResolver, string selection)
 165                 {
 166                         StyleEntry entry = new StyleEntry ();
 167                         entry.Style = style;
 168                         entry.UrlResolver = urlResolver;
 169                         entry.Selection = selection;
 170                         entries.Add (entry);
 171                 }
 172
 173                 public void RegisterStyle (Style style, IUrlResolutionService urlResolver)
 174                 {
 175                         for (int n=0; n<entries.Count; n++) {
 176                                 if (((StyleEntry)entries[n]).Style == style)
 177                                         return;
 178                         }
 179
 180                         string name = "aspnet_" + entries.Count;
 181                         style.SetRegisteredCssClass (name);
 182                         CreateStyleRule (style, urlResolver, "." + name);
 183                 }
 184
 185                 public void Render (HtmlTextWriter writer)
 186                 {
 187                         writer.AddAttribute ("type", "text/css");
 188                         writer.RenderBeginTag (HtmlTextWriterTag.Style);
 189
 190                         foreach (StyleEntry entry in entries) {
 191                                 CssStyleCollection sts = entry.Style.GetStyleAttributes (entry.UrlResolver);
 192                                 writer.Write ("\n" + entry.Selection + " {" + sts.Value + "}");
 193                         }
 194
 195                         writer.RenderEndTag ();
 196                 }
 197         }
 198 }
 199
 200 #endif