iTextSharp HTMLWorker.ParseToList（）拋出NullReferenceException

我正在使用iTextSharp v.4合併一大堆html文件。它工作正常，直到我需要升級到iTextSharp v.5。iTextSharp HTMLWorker.ParseToList（）拋出NullReferenceException

當我將流式讀取器（讀取html文件的內容）傳遞給HTMLWorker對象的ParseToList方法時，問題就出現了。它拋出一個空引用異常。在調試它時，我可以訪問streamReader並可以確認文件的正確內容被讀取。

下面是代碼：

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塊，你會看到，然後我用幾乎相同的代碼添加文本到PDF說，有一個問題。此代碼工作正常。當然，這讓我覺得，問題出在原來的HTML字符串的內容，所以這裏是字符串的內容，因爲它剛剛被傳遞到解析器之前：

<!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>

感謝您的幫助。 hofnarwillie

來源

2011-12-20 hofnarwillie

看起來HTMLWorker在兩個<hr width="100%" />窒息。既然你說你在使用V5.XX，那麼開始使用XMLWorker開始解析你的HTML也許會很好 - 開發團隊正在推薦它。（最新HTMLWorker源代碼，甚至有一個小的參考指出這一點）測試與擴展HTML

，它的工作原理，並不算太差實現:)

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; 
    } 
}

測試在網絡環境，請將Response.OutputStream替換爲您所選的Stream。

來源

2011-12-20 13:56:29 kuujinbo

感謝您的回覆。在哪裏定義了XMLWorkerHelper類？我不認爲我已經下載了iTextSharp dll。 V 5.1.3 – hofnarwillie 2011-12-20 14:21:16

發現它感謝。僅供參考：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

只是測試，完成後會標記爲答案 – hofnarwillie 2011-12-20 14:31:54

iTextSharp HTMLWorker.ParseToList（）拋出NullReferenceException

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