如何在 C# 中使用 XmlWriter class 生成以下 Xml？

Question

我想在 C# 中使用 XmlWriter class 生成以下格式的 XML -:

<?xml version="1.0" ?>
<root>
 <data>
  <entry Attrib1="" Attrib2="91.3467" Attrib3="95.3052" Attrib4="6.4722" />
  <entry Attrib1="" Attrib2="91.3467" Attrib3="95.3052" Attrib4="6.4722" />
 </data>
</root>

我是 XmlWriter class 和 C# 的新手，我尝试编写代码来生成上述格式的文件，但尝试没有成功

var xmlWriter = XmlWriter.Create(filename);
    xmlWriter.WriteStartDocument();
    xmlWriter.WriteStartElement("data");

    xmlWriter.WriteStartElement("entry");
    xmlWriter.WriteAttributeString("attrib1", "value1");
    xmlWriter.WriteAttributeString("attrib2", "value2");
    xmlWriter.Close();

此外，属性的名称可以包含非法的 XML 字符，这就是我阅读 XMLWriter 的原因，因为它似乎从属性的名称中删除了那些非法字符，例如 a当写入结果 XML 时，像 "this is attribute 1" 这样的名称应该减少到像 "this_is_attribute_1" 这样的东西，我如何使用 XmlWriter 生成这样的 XML。简而言之，结果的一行 XML 是这样的

<entry P_B_Pe="" P_E_Pe="91.3467" Custom_Price="95.3052" C_Yield="6.4722" Average_Life="" />

Answer 1

试试 XML Linq

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;
using System.IO;

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        static void Main(string[] args)
        {
            StreamWriter sWriter = new StreamWriter(FILENAME);
            XmlTextWriter writer = new XmlTextWriter(sWriter);

            writer.WriteStartDocument();
            writer.WriteStartElement("root");
            writer.WriteStartElement("data");

            double?[] attributes = new double?[] { null, 91.3467, 95.3052, 6.4722 };
            XElement entry = new XElement("entry");
            int index = 1;

            foreach (double? attribute in attributes)
            {
                if (attribute == null)
                {
                    entry.Add(new XAttribute("Attrib" + index++.ToString(), ""));
                }
                else
                {
                    entry.Add(new XAttribute("Attrib" + index++.ToString(), attribute));
                }
            }

            writer.WriteRaw(entry.ToString());
            writer.WriteRaw(entry.ToString());

            writer.WriteEndElement();
            writer.WriteEndElement();

            writer.Flush();
            writer.Close();


        }
    }
}

没有任何 xml linq then

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;
using System.IO;

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        static void Main(string[] args)
        {
            StreamWriter sWriter = new StreamWriter(FILENAME);
            XmlTextWriter writer = new XmlTextWriter(sWriter);

            writer.WriteStartDocument();
            writer.WriteStartElement("root");
            writer.WriteStartElement("data");
            writer.WriteStartElement("entry");

            double?[] attributes = new double?[] { null, 91.3467, 95.3052, 6.4722 };
            int index = 1;
            foreach (double? attribute in attributes)
            {
                writer.WriteStartAttribute("Attrib" + index++.ToString());
                if (attribute == null)
                {
                    writer.WriteValue("");
                }
                else
                {
                    writer.WriteValue(attribute);
                } 
                writer.WriteEndAttribute();

            }

            writer.WriteEndElement();

            writer.WriteStartElement("entry");
            attributes = new double?[] { null, 91.3467, 95.3052, 6.4722 };
            index = 1;
            foreach (double? attribute in attributes)
            {
                writer.WriteStartAttribute("Attrib" + index++.ToString());
                if (attribute == null)
                {
                    writer.WriteValue("");
                }
                else
                {
                    writer.WriteValue(attribute);
                }
                writer.WriteEndAttribute();

            }

            writer.WriteEndElement();

            writer.WriteEndElement();
            writer.WriteEndElement();

            writer.Flush();
            writer.Close();


        }
    }
}

Answer 2

你快搞定了...

var xmlWriter = XmlWriter.Create(filename);
    xmlWriter.WriteStartDocument();
        xmlWriter.WriteStartElement("root");
            xmlWriter.WriteStartElement("data");
                xmlWriter.WriteStartElement("entry");
                    xmlWriter.WriteAttributeString("attrib1", "value1");
                    xmlWriter.WriteAttributeString("attrib2", "value2");
                xmlWriter.WriteEndElement(); // entry
                xmlWriter.WriteStartElement("entry");
                    xmlWriter.WriteAttributeString("attrib1", "value1");
                    xmlWriter.WriteAttributeString("attrib2", "value2");
                xmlWriter.WriteEndElement(); // entry
            xmlWriter.WriteEndElement(); // data
        xmlWriter.WriteEndElement(); // root
    xmlWriter.WriteEndDocument();
xmlWriter.Close();

默认情况下，XmlWriter 会对原始数据或属性值中通常无效的字符进行编码，这样当您使用 reader 解码 XML，但属性和元素名称必须仍然有效。如果您想以某种不同于此的特殊方式处理那些无效字符，则需要根据您要建立的任何规则自己执行此操作，例如：

xmlWriter.WriteAttributeString(MyXmlExtensions.EncodeXmlAttributeName("this is normally an invalid attribute name"), "value1");

class MyXmlExtensions
{
    public string EncodeXmlAttributeName(string decoded)
    {
        // not that you'll likely need to enhance this with whatever rules you want but haven't specified
        return decoded.Replace(" ", "_");
    }
    public string DecodeXmlAttributeName(string encoded)
    {
        // not that you'll likely need to enhance this with whatever rules you want but haven't specified
        return encoded.Replace("_", " ");
    }
}

如果您希望输出看起来漂亮（制表符、多行等），您还需要在对 XmlWriter.Create 的调用中使用 XmlWriterSettings。

Answer 3

使用对象序列化，就不需要对象到结构的映射代码了

using System.Xml.Serialization;

...

[XmlRoot("root")]
public class Example {
    [XmlElement("data")]
    public Entries Entries { get; set; }
}

public class Entries : List<List<string>>, IXmlSerializable {

    public List<string> Attribs { get; set; }

    public System.Xml.Schema.XmlSchema GetSchema() { return null; }

    public void ReadXml(System.Xml.XmlReader reader) { reader.MoveToContent(); }

    public void WriteXml(System.Xml.XmlWriter writer) {
        foreach (var entry in this) {
            writer.WriteStartElement("entry", "");
            var label = 1;
            foreach (var attrib in entry) {
                writer.WriteAttributeString(string.Format("Attrib{0}", label), attrib);
                label++;
            }
            writer.WriteEndElement();
        }
    }
}

...

var xml = new XmlSerializer(typeof(Example), "");
xml.Serialize(stream, example);

如何在 C# 中使用 XmlWriter class 生成以下 Xml？

How do I generate the following Xml using XmlWriter class in C#?

.net

c#

xml

xmlwriter

xmltextwriter