ASP.NET 2.0: MasterPage HtmlHead Renders Messy HTML

Anatoly Lubarsky
MSSQL, .NET, Design. Life and Music

ASP.NET 2.0: MasterPage HtmlHead Renders Messy HTML

This bug in MasterPage's HtmlHead control rendering is rather annoying to say the least. If head element is specified as runat="server" at design time it seems that ASP.NET renders all previously design-time defined tags as one literal control, which means - it renders all tags as one long string eating all line-breaks. Suppose the following head element in MasterPage markup like so:

< !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 
Transitional//EN" "DTD/xhtml1-transitional.dtd">
< html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
< head runat="server">
< title>< /title>
< meta http-equiv="content-type" content="text/html; charset=utf-8" />
< meta name="keywords" content="mykwords" />
< link href="/mycss.css" type="text/css" rel="stylesheet" />
< /head>

Now I go and set the title in the content page like so:

this.Header.Title = "My Title";

Expecting to get just the same markup for my head element with title string just inside title tag. I don't expect head element to be totally reformatted !

Instead, what I get is:

All design-time tags are rendered as one long string without line-breaks.
Title tag is rendered without line-break before and after.
Title tag has 2 additional line-breaks before and after its innerHtml.
Title tag has additional tab character after the line-break before its innerHtml starts.

LOL. Somebody has to take care of this...

Wednesday, January 10, 2007 4:25 AM

Comments

# re: ASP.NET 2.0: MasterPage HtmlHead Renders Messy HTML

This stupid behavior can be overriden using control adapters. I've written three classes for <head>, <meta> and <link> controls so that they render nice html.

But there's a problem with CSS rules added to HtmlHead through StyleSheet property. I don't use it but think that is should be implemented for sake of consistency. The class that renders it's html code is marked internal and i can't find a way make it render to specific HtmlWriter.

The code is quite short (<100 lines) and i can copy it here if you need it.

1/29/2007 3:43 PM by Bazile

# re: ASP.NET 2.0: MasterPage HtmlHead Renders Messy HTML

Bazile: thanks for the tip.

You can post the code if you want. I promise to make a post of it later and give you full credit.

1/29/2007 9:22 PM by Anatoly Lubarsky

# re: ASP.NET 2.0: MasterPage HtmlHead Renders Messy HTML

1) Control adapters source. It can be compiled into your assembly or placed into App_Code folder.
---------------------------------------------------------------------
using System;
using System.Collections;
using System.Web.UI;
using System.Web.UI.HtmlControls;

namespace YourNamespace
{
public class HtmlHeadAdapter : System.Web.UI.Adapters.ControlAdapter
{
protected override void Render(HtmlTextWriter writer)
{
writer.WriteLine("<head>");
HtmlHead headTag = (HtmlHead)this.Control;
ControlCollection controls = headTag.Controls;
for (int i=0; i<controls.Count; i++)
{
Control c = controls[i];
headTag.Controls[i].RenderControl(writer);
}
// Стили - yet to be implemented
/*if (this.Page.Request.Browser["requiresXhtmlCssSuppression"] != "true")
{
headTag.StyleSheet.Render();
}*/
// Заголовок
writer.Write("<title>");
writer.Write(Page.Title);
writer.WriteLine("</title>");
writer.Write("</head>");
}
}

public class HtmlLinkAdapter : System.Web.UI.Adapters.ControlAdapter
{
protected override void Render(HtmlTextWriter writer)
{
HtmlLink linkTag = (HtmlLink)this.Control;
writer.Write("<link");
AttributeCollection attributes = linkTag.Attributes;
IEnumerator keys = linkTag.Attributes.Keys.GetEnumerator();
while (keys.MoveNext())
{
string key = (string)keys.Current;
writer.Write(" ");
writer.Write(key);
writer.Write("=\"");
writer.Write(attributes[key]);
writer.Write("\"");
}
writer.WriteLine(">");
}
}

public class HtmlMetaAdapter : System.Web.UI.Adapters.ControlAdapter
{
protected override void Render(HtmlTextWriter writer)
{
HtmlMeta metaTag = (HtmlMeta)this.Control;
writer.Write("<meta http-equiv=\"");
writer.Write(metaTag.HttpEquiv);
writer.Write("\" content=\"");
writer.Write(metaTag.Content);
writer.WriteLine("\">");
}
}
}
---------------------------------------------------------------------

2) To register control adapters create folder App_Browsers in the root of your web application. Then create a file named Default.browser with this content:

<browsers>
<browser refID="Default">
<controlAdapters>
<adapter
controlType="System.Web.UI.HtmlControls.HtmlHead"
adapterType="YourNamespace.HtmlHeadAdapter"
/>
<adapter
controlType="System.Web.UI.HtmlControls.HtmlLink"
adapterType="YourNamespace.HtmlLinkAdapter"
/>
<adapter
controlType="System.Web.UI.HtmlControls.HtmlMeta"
adapterType="YourNamespace.HtmlMetaAdapter"
/>
</controlAdapters>
</browser>
</browsers>

1/30/2007 10:20 AM by Bazile

# ASP.NET 2.0: Override MasterPage HtmlHead Rendering with ControlAdapters

1/31/2007 1:28 AM by Anatoly Lubarsky

# ASP.NET 2.0: HtmlHead Rendering ControlAdapters implementation

1/31/2007 2:51 AM by Anatoly Lubarsky

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