Stream based XML file operation notes in C

System.Xml.XmlReader and System.Xml.XmlWriters are two abstract classes. XmlReader provides a fast, non-cached, feed-only reader for XML data. XmlWriter represents a writer that provides a fast, non-cached, forward-only way to generate stream files containing XML data.

XmlReader is similar to the SAX reader, but the former is the extract mode (read-only cursor) and the latter is the push mode (push events to the application).

The advantages of XmlReader are:
1. Simplify state management
2. There can be multiple input streams
3. Extraction mode can be used as the basis of push mode, but not vice versa.
4. Provide a buffer where strings can be written directly to avoid duplication of extra bytes.
5. Optionally, XML streams can be processed in a way that is preset for XML streams.
The code logic below is simple and does not cause exceptions, so exception handling is not added, but is used as a test.

// ReadXml.cs
// XmlReader Example 

using System;
using System.Xml;

class Test
{
  public static void Main(string[] args)
  {
    string path = @"G:\ data \C# object-oriented programming \C# object-oriented programming \CSharp\Chapter17\books.xml";
    XmlReader reader = null;
    try
    {
      //  Establish XmlReaderSettings object 
      XmlReaderSettings settings = new XmlReaderSettings();
      //  Set up XmlReaderSettings Object Properties 
      settings.ProhibitDtd = false;
      //  Use XmlReaderSettings Object to create XmlReader object 
      reader = XmlReader.Create(path, settings);
      ReadXml(reader);
      reader.Close();
      Console.ReadKey();
    }
    catch (Exception ex)
    {
      Console.WriteLine(ex.Message);
    }
    finally
    {
      if (reader != null)
        reader.Close();
    }
  }

  private static void ReadXml(XmlReader reader)
  {
    try
    {
      //  Parse the file and display each 1 Nodes 
      while (reader.Read())
      {
        switch (reader.NodeType)
        {
          case XmlNodeType.Element:
            if (reader.IsEmptyElement) //  Empty element? 
            {
              Console.WriteLine("<{0}/>", reader.Name);
            }
            else
            {
              Console.Write("<{0}", reader.Name);
              if (reader.HasAttributes)  //  Attributes? 
              {
                while (reader.MoveToNextAttribute())
                {
                  Console.Write(" {0}=\"{1}\"", reader.Name, reader.Value);
                }
              }
              Console.WriteLine(">", reader.Name);
            }
            break;
          case XmlNodeType.Text:
            Console.WriteLine(reader.Value);
            break;
          case XmlNodeType.CDATA:
            Console.WriteLine("<![CDATA[{0}]]>", reader.Value);
            break;
          case XmlNodeType.ProcessingInstruction:
            Console.WriteLine("<?{0} {1}?>", reader.Name, reader.Value);
            break;
          case XmlNodeType.Comment:
            Console.WriteLine("<!--{0}-->", reader.Value);
            break;
          case XmlNodeType.XmlDeclaration:
            Console.WriteLine("<?xml version='1.0'?>");
            break;
          case XmlNodeType.Document:
            break;
          case XmlNodeType.DocumentType:
            Console.WriteLine("<!DOCTYPE {0} [{1}]>", reader.Name, reader.Value);
            break;
          case XmlNodeType.EntityReference:
            Console.WriteLine(reader.Name);
            break;
          case XmlNodeType.EndElement:
            Console.WriteLine("</{0}>", reader.Name);
            break;
        }
      }
    }
    catch (XmlException ex)
    {
      Console.WriteLine(ex.Message);
    }
  }
}

XmlWriters This writer provides a fast, non-cached, forward-only way to generate streaming files containing XML data, with essentially the same benefits as the former.
Note: With XmlReader, elements and attributes are not read until the Close method is called.

XMLWriter
using System.Xml;

namespace ConsoleApplication1
{
  class Program
  {
    static void Main(string[] args)
    {
      string path=@"C:\Users\dell\Desktop\test.xml";
      XmlWriter writer=null;
      XmlWriterSettings settings = new XmlWriterSettings();
      settings.Indent = true;
      settings.IndentChars=("");
      writer = XmlWriter.Create(path, settings);
      WriteXml(writer);
      writer.Close();
    }
    private static void WriteXml(XmlWriter writer)
    {
      writer.WriteStartElement("books");
      WriteChildNode(writer, " The Dream of Red Mansion ", " Cao Xueqin ", "25");
      WriteChildNode(writer, "3 National Romance ", " Luo Guanzhong ", "20");
      WriteChildNode(writer, " Water Margin ", " Shi Nai'an ", "18");
      WriteChildNode(writer, " Liao Zhai Zhiyi ", " Pu Songling ", "16");
      writer.WriteEndElement();
    }
    private static void WriteChildNode(XmlWriter writer, string title, string author, string price)
    {
      writer.WriteStartElement("book");

      writer.WriteStartElement("title");
      writer.WriteValue(title);
      writer.WriteEndElement();

      writer.WriteStartElement("author");
      writer.WriteValue(author);
      writer.WriteEndElement();
      
      writer.WriteStartElement("price");
      writer.WriteValue(price);
      writer.WriteEndElement();

      writer.WriteEndElement();
    }
  }
}

The basic usage is simple, that is, to output the front and back switch labels, mainly using the three methods WriteStartElement () writer.WriteValue () WriteEndElement ()
Note: When the XmlWriter method outputs XML, elements and attributes are not written until the Close method is called.