iTextSharp HTMLWorker.ParseToList（）抛出NullReferenceException

我正在使用iTextSharp v.4合并一大堆html文件。它工作正常，直到我需要升级到iTextSharp v.5。iTextSharp HTMLWorker.ParseToList（）抛出NullReferenceException

当我将流式读取器（读取html文件的内容）传递给HTMLWorker对象的ParseToList方法时，问题就出现了。它抛出一个空引用异常。在调试它时，我可以访问streamReader并可以确认文件的正确内容被读取。

下面是代码：

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，你会看到，然后我用几乎相同的代码添加文本到PDF说，有一个问题。此代码工作正常。当然，这让我觉得，问题出在原来的HTML字符串的内容，所以这里是字符串的内容，因为它刚刚被传递到解析器之前：

<!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;"> 
         &nbsp; 
        </td> 
        <td> 
        </td> 
        <td style="width: 30mm; height: 1px; line-height: 1px; font-size: 1px;"> 
         &nbsp; 
        </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 &amp; 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;"> 
        
        </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

来源

2011-12-20 hofnarwillie

看起来HTMLWorker在两个<hr width="100%" />窒息。既然你说你在使用V5.XX，那么开始使用XMLWorker开始解析你的HTML也许会很好 - 开发团队正在推荐它。（最新HTMLWorker源代码，甚至有一个小的参考指出这一点）测试与扩展HTML

，它的工作原理，并不算太差实现:)

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; 
    } 
}

测试在网络环境，请将Response.OutputStream替换为您所选的Stream。

来源

2011-12-20 13:56:29 kuujinbo

感谢您的回复。在哪里定义了XMLWorkerHelper类？我不认为我已经下载了iTextSharp dll。 V 5.1.3 – hofnarwillie 2011-12-20 14:21:16

发现它感谢。仅供参考：http://sourceforge.net/projects/itextsharp/files/xmlworker/xmlworker-1.1.1/itextsharp.xmlworker-all-1.1.1.zip/download – hofnarwillie 2011-12-20 14:31:07

只是测试，完成后会标记为答案 – hofnarwillie 2011-12-20 14:31:54

iTextSharp HTMLWorker.ParseToList（）抛出NullReferenceException

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