如何获取XFA表单中的字段列表？ [英] How to get a list of the fields in an XFA form?

问题描述

我正在尝试获取XFA表单中所有字段的简单列表。我正在使用此代码：

  private void ListFieldNames（）
 {
 string pdfTemplate = @C ：\Projects\iTextSharp\SReport.pdf; 
 MemoryStream m = new MemoryStream（）; 
 
 //标题形式
 this.Text + = - + pdfTemplate; 
 
 //基于PDF模板文档创建一个新的PDF阅读器
 PdfReader pdfReader = new PdfReader（pdfTemplate）; 
 PdfStamper pdfStamper = new PdfStamper（pdfReader，m）; 
 AcroFields formFields = pdfStamper.AcroFields; 
 AcroFields form = pdfReader.AcroFields; 
 XfaForm xfa = form.Xfa; 
 StringBuilder sb = new StringBuilder（）; 
 sb.Append（xfa.XfaPresent？XFA form：AcroForm）; 
 sb.Append（Environment.NewLine）; 
 
 foreach（form.Fields.Keys中的字符串键）
 {
 sb.Append（key）; 
 sb.Append（Environment.NewLine）; 
 txtFields.Text = sb.ToString（）; 
} 
 
 txtFields.Text = sb.ToString（）; 
} 
  

但我得到的只是XFA表格，而不是任何字段。知道我做错了什么吗？

提前致谢

解决方案

您已经采用了代码示例从我的书iText in Action的第8章开始。该代码示例的结果与我在第273页上所写的内容一致：

使用此运行清单8.18 form as resource将给你以下结果：

AcroForm

如果你的问题是我知道我做错了吗？那么答案很简单：你停止阅读页面270，或者您使用了代码示例而未阅读随附的文档。如何解决这个问题？阅读文档！

如果您的问题是为什么我没有获得有关这些字段的任何信息？（这不是您的问题，但我们假设它是），答案是：您使用代码来检索AcroForm字段，但您的表单不包含任何此类字段。您的表单是纯XFA表单，这意味着所有字段信息仅存储为XML和XML！

假设您现在想知道：怎么能我提取了那些XML？然后你应该去你找到你复制/粘贴的例子的地方。

这可能在这里：
http://itextpdf.com/examples/iia.php?id=164

或者在这里： http://sourceforge.net/p/itextsharp/code/HEAD/tree/trunk/book/iTextExamplesWeb/iTextExamplesWeb/iTextInAction2Ed/Chapter08/XfaMovie.cs

甚至在这里： http://kuujinbo.info/iTextInAction2Ed/index.aspx?ch=Chapter08&ex=XfaMovie

此代码段将返回完整的XFA流：

  public string ReadXfa（PdfReader reader）{
 XfaForm xfa = new XfaForm（读取器）; 
 XmlDocument doc = xfa.DomDocument; 
 reader.Close（）; 
 
 if（！string.IsNullOrEmpty（doc.DocumentElement.NamespaceURI））{
 doc.DocumentElement.SetAttribute（xmlns，）; 
 XmlDocument new_doc = new XmlDocument（）; 
 new_doc.LoadXml（doc.OuterXml）; 
 doc = new_doc; 
} 
 
 var sb = new StringBuilder（4000）; 
 var Xsettings = new XmlWriterSettings（）{Indent = true}; 
 using（var writer = XmlWriter.Create（sb，Xsettings））{
 doc.WriteTo（writer）; 
} 
返回sb.ToString（）; 
} 
  

现在查找< xfa：datasets> 标签;它将有一个子标签< xfa：data> （如果表格为空，则可能为空）和子标签< dd：dataDescription> 。在 dataDescription 标记内，您会发现类似于XSD的内容。这就是你需要知道表格中的字段是什么。

我可以继续猜测问题，例如：我如何填写这样的form？使用方法 fillXfaForm（）; 如何展平这样的表单？通过使用XFA Worker（这是一个在iTextSharp上编写的封闭源库），但让我们将这些问题留给另一个线程; - ）

I am trying to get a simple list of all the fields in my XFA form. I am using this code:

private void ListFieldNames()
{
    string pdfTemplate = @"C:\Projects\iTextSharp\SReport.pdf";
    MemoryStream m = new MemoryStream();

    // title the form
    this.Text += " - " + pdfTemplate;

    // create a new PDF reader based on the PDF template document
    PdfReader pdfReader = new PdfReader(pdfTemplate);
    PdfStamper pdfStamper = new PdfStamper(pdfReader, m);
    AcroFields formFields = pdfStamper.AcroFields;        
    AcroFields form = pdfReader.AcroFields;
    XfaForm xfa = form.Xfa;
    StringBuilder sb = new StringBuilder();
    sb.Append(xfa.XfaPresent ? "XFA form" : "AcroForm");
    sb.Append(Environment.NewLine);

    foreach (string key in form.Fields.Keys)
    {
        sb.Append(key);
        sb.Append(Environment.NewLine);
        txtFields.Text = sb.ToString();
    }

    txtFields.Text = sb.ToString();
}

But all I am getting is the XFA Form and not any fields. Any idea what I am doing wrong?

Thanks in advance

解决方案

You've taken a code sample from chapter 8 of my book "iText in Action." The result of that code sample is consistent with what I wrote on page 273:

Running Listing 8.18 with this form as resource will give you the following result:

AcroForm

If your question is Any idea what I am doing wrong? then the answer is simple: you stopped reading on page 270, or you used a code sample without reading the accompanying documentation. How to fix this? Read the documentation!

If your question is Why don't I get any info about the fields? (which isn't your question, but let's assume it is), the answer is: you're using code to retrieve AcroForm fields, but your form doesn't contain any such fields. Your form is a pure XFA form, which means that all field information is stored as XML and XML only!

Suppose that you now want to know: How can I extract that XML? then you should go to the place where you found the example you copy/pasted.

That could be here: http://itextpdf.com/examples/iia.php?id=164

Or maybe here: http://sourceforge.net/p/itextsharp/code/HEAD/tree/trunk/book/iTextExamplesWeb/iTextExamplesWeb/iTextInAction2Ed/Chapter08/XfaMovie.cs

Or even here: http://kuujinbo.info/iTextInAction2Ed/index.aspx?ch=Chapter08&ex=XfaMovie

This code snippet will return the complete XFA stream:

public string ReadXfa(PdfReader reader) {
  XfaForm xfa = new XfaForm(reader);
  XmlDocument doc = xfa.DomDocument;
  reader.Close();

  if (!string.IsNullOrEmpty(doc.DocumentElement.NamespaceURI)) {
    doc.DocumentElement.SetAttribute("xmlns", "");
    XmlDocument new_doc = new XmlDocument();
    new_doc.LoadXml(doc.OuterXml);
    doc = new_doc;
  }

  var sb = new StringBuilder(4000);
  var Xsettings = new XmlWriterSettings() {Indent = true};
  using (var writer = XmlWriter.Create(sb, Xsettings)) {
    doc.WriteTo(writer);
  }
  return sb.ToString();    
}

Now look for the <xfa:datasets> tag; it will have a subtag <xfa:data> (probably empty if the form is empty) and a subtag <dd:dataDescription>. Inside the dataDescription tag, you'll find something that resembles XSD. That's what you need to know what the fields in the form are about.

I could go on guessing questions, such as: How do I fill out such a form? By using the method fillXfaForm(); How can I flatten such a form? By using XFA Worker (which is a closed source library written on top of iTextSharp), but let's keep those questions for another thread ;-)

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