如何加载内联DTD以用于XDocument?

时间:2011-07-07 12:30:36

标签: c# xml windows-phone-7 linq-to-xml dtd-parsing

我有一个问题,关于如何将文档类型定义包含到XML文件中,或者从WP7中加载到XDocument中的XML文件中。我有与此类似的DTD文件:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE root [
 <!ELEMENT root (Person*)>

 <!ELEMENT Person (Name*, Description*)>
 <!ELEMENT Name (#PCDATA)>
 <!ELEMENT Description (#PCDATA)>

 <!ENTITY egrave "&#232;">
 <!ENTITY eacute "&#233;">
 <!ENTITY euro  "&#8364;">
]>

我需要将此DTD添加到XML中,以便捕获特殊字符,例如&eacute;。 我使用以下方法从Web获取XML以在Linq中使用:

private void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e)
{
  string documentUrl = "http://www.example.com";

  WebClient client = new WebClient();

  client.OpenReadCompleted += new OpenReadCompletedEventHandler(client_OpenReadCompleted);
  client.OpenReadAsync(new Uri(documentUrl, UriKind.Absolute));
}

void client_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
  Stream str = e.Result;

  XDocument data = XDocument.Load(str);

  // Saving the XML to the file system for later use
  IsolatedStorageFile isoFile = IsolatedStorageFile.GetUserStoreForApplication();
  IsolatedStorageFileStream isoStream = new IsolatedStorageFileStream("my.xml", FileMode.OpenOrCreate, isoFile);
  StreamWriter sw = new StreamWriter(isoStream);
  XmlWriter xw = XmlWriter.Create(isoStream);

  data.Save(xw);

  // Creating a list to populate a listbox
  List<MyObject> list1 = new List<MyObject>();

  items = (from query in data.Descendants("Person")
    select new MyObject()
    {
    // Doing stuff here...
    }).ToList();

  listBox1.ItemsSource = items;

}

如果DTD是内联的,即在实际的XML本身中,XDocument似乎不会传递XML。 我已经尝试了许多基于this帖子使用XDocumentType的方法,但我无法弄清楚。 我怎么能这样做?

1 个答案:

答案 0 :(得分:5)

您需要在阅读XML文档时启用DTD处理。为此,请使用XmlReader并使用适当的设置:

var settings = new XmlReaderSettings { DtdProcessing = DtdProcessing.Parse };
XmlReader reader = XmlReader.Create(str, settings);
XDocument data = XDocument.Load(reader);

如果您想让DTD在外部,您需要在设置中指定XmlResolver

var settings = new XmlReaderSettings
{
    DtdProcessing = DtdProcessing.Parse,
    XmlResolver = /* some resolver here */,
};

默认XmlResolverXmlUrlResolver,可在不使用凭据的情况下解析网址。您可能需要考虑从本地源解析DTD。为此,您可以使用预先填充的XmlPreloadedResolver