如何用System.Xml.XmlDocument解析HTML？转换及解析报错求助

Let's break down what's going on here and how to fix these issues so you can get that HTML converted to valid XHTML for your C# XML parsing:

1. Invalid Character Warnings (Codes 128 and 153) #

The warnings about replacing invalid characters (128 and 153) stem from encoding mismatches or non-XML-compliant characters:

• Code 128 is a control character that’s not allowed in standard XML.
• Code 153 is the trademark symbol (™), a Windows-1252 character that might not be properly encoded in your input HTML.

Fixes: #

• Specify the input encoding when running tidy. If your HTML uses Windows-1252, use this command:

  tidy -asxhtml -m -encoding windows-1252 index.html
  

• Preserve raw characters instead of replacing them (if you need to keep symbols like ™):

  tidy -asxhtml -m -raw index.html
  

• Pre-process in C#: Before running tidy, clean the HTML to remove or replace invalid XML characters. For example, filter out disallowed control characters:

  string cleanedHtml = new string(originalHtml.Where(c => XmlConvert.IsXmlChar(c)).ToArray());
  

2. Unrecognized Content Errors (Lines 121, 125) #

The "无法识别！" (unrecognized) errors mean tidy hit malformed HTML syntax it can’t fix automatically—this is almost always broken tags or invalid structure.

Fixes: #

• Inspect the problematic lines: Open index.html and check lines 121 and 125 for common issues like:
  • Unclosed tags (e.g., <div> without a matching </div>)
  • Missing quotes around attributes (e.g., <div class=foo> instead of <div class="foo">)
  • Custom elements tidy doesn’t recognize (use -new-blocklevel-tags or -new-inline-tags to whitelist them if needed)
• Manually correct the syntax: Fix the broken HTML in those lines, then re-run tidy—these errors should vanish.

3. Verify the Final XHTML for C# Parsing #

After resolving tidy’s warnings/errors, confirm the output XHTML is well-formed (a must for C# XML parsing):

• Use C#'s XmlReader to test parsing directly:

  using (XmlReader reader = XmlReader.Create("index.html")) {
      while (reader.Read()) {
          // Iterate through to catch any remaining parsing errors
      }
  }
  

• If errors persist, double-check for unclosed tags or leftover invalid characters tidy might have missed.

Remember: HTML is built to be forgiving, but XML (and XHTML) is strict. Tidy is a powerful tool, but it can’t fix every edge case—manual checks for broken syntax are often necessary.

内容的提问来源于stack exchange，提问作者Don't Know