c# - XmlReader和MemoryStream，返回的xml misses标签

有人可以向我解释这种行为吗？

如果您使用第一个字符串在帖子底部执行代码段，它将返回与用于输入的字符串完全相同的字符串。这就是我所期望的。

输入1：

<?xml version='1.0' encoding='UTF-8'?>
<Company>
  <Creator>Me</Creator>
  <CreationDateTime>2010-01-25T21:58:32.493</CreationDateTime>
  <Contacts>
    <Contact>
      <ContactID>365</ContactID>
    </Contact>
  </Contacts>
</Company>

输出1：

<?xml version='1.0' encoding='UTF-8'?>
<Company>
  <Creator>Me</Creator>
  <CreationDateTime>2010-01-25T21:58:32.493</CreationDateTime>
  <Contacts>
    <Contact>
      <ContactID>365</ContactID>
    </Contact>
  </Contacts>
</Company>

现在，如果您使用第二行（const string xml），该行确实是相同的字符串，但是一行而不是两行，则返回以下内容

输入2

<?xml version='1.0' encoding='UTF-8'?>
<Company>
  <Creator>Me</Creator>
  <CreationDateTime>2010-01-25T21:58:32.493</CreationDateTime>
  <Contacts>
    <Contact>
      <ContactID>365</ContactID>
    </Contact>
  </Contacts>
</Company>

输出2

<?xml version='1.0' encoding='UTF-8'?>
<Creator>Me</Creator>2010-01-25T21:58:32.493
<Contacts>
  <Contact>
    <ContactID>365</ContactID>
  </Contact>
</Contacts>

2之间的唯一区别是，第一个在xml声明之后有一个换行符，但是如您所见，第二个输出缺少Parent标记，而第三个标记则丢失。任何想法？

这是我使用的代码：

public void XmlReader_Eats_Tags_IsTrue()
    {
        //this first xml declaration is on two lines - line break is right after the xml declaration (I am not sure how to add the line break using the markdown, so if you execute the code on your machine, please add it)
        const string xml = @"<?xml version='1.0' encoding='UTF-8'?><Company><Creator>Me</Creator><CreationDateTime>2010-01-25T21:58:32.493</CreationDateTime><Contacts><Contact><ContactID>365</ContactID></Contact></Contacts></Company>";

        //The seconde xml declaration is on one line
        //const string xml = @"<?xml version='1.0' encoding='UTF-8'?><Company><Creator>Me</Creator><CreationDateTime>2010-01-25T21:58:32.493</CreationDateTime><Contacts><Contact><ContactID>365</ContactID></Contact></Contacts></Company>";

        BufferedStream stream = new BufferedStream(new MemoryStream());
        stream.Write(Encoding.ASCII.GetBytes(xml), 0, xml.Length);
        stream.Seek(0, SeekOrigin.Begin);
        StreamReader streamReaderXml = new StreamReader(stream);

        XmlReader xmlR = XmlReader.Create(streamReaderXml);

        XmlReaderSettings xmlReaderset =
                         new XmlReaderSettings{ValidationType = ValidationType.Schema};
        xmlReaderset.Schemas.ValidationEventHandler += ValidationCallBack;

        MemoryStream ms = new MemoryStream();
        XmlWriterSettings xmlWriterSettings =
                          new XmlWriterSettings{
                                  Encoding = new UTF8Encoding(false),
                                  ConformanceLevel = ConformanceLevel.Fragment
                          };

        using (XmlWriter xmlTw = XmlWriter.Create(ms, xmlWriterSettings))
        {
            using (XmlReader xmlRead = XmlReader.Create(xmlR, xmlReaderset))
            {
                int i = 0;
                while (xmlRead.Read())
                {
                    Console.WriteLine("{0}:{1}; node type: {2}", i, xmlRead.Name, xmlRead.NodeType);
                    // Reads the whole file and will call the validation handler subroutine if an error is detected.
                    xmlTw.WriteNode(xmlRead, true);
                    i++;
                }

                xmlTw.Flush();
                xmlRead.Close();
            }
            string xmlString = Encoding.UTF8.GetString(ms.ToArray());
            Console.WriteLine(xmlString);
        }
    }

最佳答案

问题是您正在使用XmlWriter.WriteNode(reader, true)并调用XmlReader.Read()。 WriteNode已经将阅读器移到了同级元素上，因此，当您再次调用Read时，实际上可以跳过数据。

我怀疑它恰好在第一个版本中起作用，因为您在第二次调用Read时跳过了空格，然后在第二次调用WriteNode时读取了文档的其余部分。