我正在使用iTextSharp v.4来合并一大堆html文件。它工作正常，直到我需要升级到iTextSharp的第5版。
当我将流读取器（读取html文件的内容）传递到HTMLWorker对象的ParseToList方法时，问题出现了。它抛出一个空引用异常。在调试它时，我可以访问streamReader并确认读取了正确的文件内容。
以下是代码：
List<IElement> objects;
try
{
objects = HTMLWorker.ParseToList(new StringReader(htmlString), null);
}
catch (Exception e)
{
htmlString = "<html><head></head><body><br/><br/><h2 style='color:#FF0000'>ERROR READING FILE!</h2><h3>File Excluded From Stitched Document!</h3><br/><br/><p>There was an error while trying to read the following file:</p><p><span style='color:#FF0000'>" + fileName + "</span></p></body></html>";
objects = HTMLWorker.ParseToList(new StringReader(htmlString), null);
}
在catch块中你会看到我然后使用几乎相同的代码将文本添加到pdf中以表示存在问题。这段代码工作正常。这当然让我觉得问题在于原始html字符串的内容，所以这里是字符串的内容，因为它在传递给解析器之前就已经存在了：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<meta http-equiv="Pragma" content="no-cache" />
<meta http-equiv="cache-control" content="no-cache" />
</head>
<body style="font-family: Arial, Helvetica, sans-serif; font-size: 1em; margin: 0;
padding: 0;">
<div style="font-size: 1em; line-height: 1.25em; width: 190mm;">
<h1 style="font-size: 1.5em; font-weight: bold; margin: 0 0 1.5em 0; text-align: center;">
Advice Item 1</h1>
<table border="0" style="width: 190mm; border-collapse: collapse; margin: 0 0 1.5em 0;
width: 100%;">
<tbody>
<tr>
<td style="width: 35mm; height: 1px; line-height: 1px; font-size: 1px;">
</td>
<td>
</td>
<td style="width: 30mm; height: 1px; line-height: 1px; font-size: 1px;">
</td>
<td>
</td>
</tr>
<tr>
<td colspan="4" style="font-weight: bold;">
<span id="litPatchedToCC" style="text-align: right; font-weight: bold;"></span>
</td>
</tr>
<tr>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
By:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
ABC
</td>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
From:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
CC
</td>
</tr>
<tr>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Date:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
29/03/2011 13:35
</td>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
To:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
Member Practice
</td>
</tr>
<tr>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Folder:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
A15-123456
</td>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Individual:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
Miss A B Test
</td>
</tr>
<tr>
<td colspan="2">
<hr width="100%" />
</td>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Of:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
Lorem & Ipsum
</td>
</tr>
<tr>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Species:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
Bovine
</td>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Position:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
Member
</td>
</tr>
<tr>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Item Type:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
</td>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Tel:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
0123 01234
</td>
</tr>
<tr>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
</th>
<td style="font-weight: bold; padding: 2px 5px;">
</td>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Other Nos:
</th>
<td style="font-weight: bold; padding: 2px 5px;">
</td>
</tr>
<tr>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Reason For Call:
</th>
<td colspan="3" style="font-weight: bold; padding: 2px 5px;">
Some Reason
</td>
</tr>
<tr>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
Subject:
</th>
<td colspan="3" style="font-weight: bold; padding: 2px 5px;">
Some problem.
</td>
</tr>
<tr>
<th scope="row" style="text-align: right; font-weight: normal; padding: 2px 5px;">
</th>
<td>
</td>
<th scope="row" colspan="2" style="text-align: right; font-weight: normal; padding: 2px 5px;">
</th>
<td colspan="2">
</td>
</tr>
<tr>
<td style="font-size: 1.5em; font-weight: bold; text-align: center;" colspan="4">
Internal
</td>
</tr>
<tr>
<td colspan="4" style="text-align: center; padding: 2px 5px;">
<hr width="100%" />
</td>
</tr>
</tbody>
</table>
<div style="padding: 2px 5px;">
<p>
Here we start the discussion.</p>
<br />
<p>
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<br />
<p>
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
</div>
</div>
</body>
</html>
感谢您的帮助。 hofnarwillie
答案 0 :(得分：7)
看起来HTMLWorker在两个<hr width="100%" />上窒息。既然你说你正在升级到V5.XX，那么开始使用XMLWorker开始解析你的HTML可能也是一件好事 - 开发团队正在推荐它。 （最新的HTMLWorker源代码甚至有一个小的引用指出这一点）
使用扩展的HTML进行测试，它可以正常工作，并且实现起来也不错：）
using (Document document = new Document()) {
PdfWriter writer = PdfWriter.GetInstance(document, Response.OutputStream);
document.Open();
try {
StringReader sr = new StringReader(htmlString);
XMLWorkerHelper.GetInstance().ParseXHtml(
writer, document, sr
);
}
catch (Exception e) {
throw;
}
}
在网络环境中测试，因此请使用您选择的Response.OutputStream替换Stream。