在 C# 中使用 XML 阅读器获取嵌套值

Question

I have a problem where I am trying to get the values of my nested elements in my XML file.

-<Modules>
 -<Modules4>
   -<Module>
       <Name>dasd</Name>
       <Code>dasdasdas</Code>
       <Credits>40</Credits>
    </Module>
   -<Module>
     <Name>dasdasd</Name>
     <Code>dasdasd</Code>
     <Credits>40</Credits>
   </Module>
</Modules4>

 <Modules5/>

 <Modules6/>

 </Modules>

This is the XML file, i am trying to create a condition where if the reader finds the "Modules4" Element, then get the nested elements "Name", "Code" and "Credits" if this question has been answered, please direct me to it as I can not find it anywhere.

    using (XmlReader reader = XmlReader.Create("SavedData.xml"))
            while (reader.Read())
        {
                if (reader.IsStartElement())
                {
                    if (reader.Name == "Modules4"){

                    switch (reader.Name)
                    {
                        case "Name":
                            string name = reader.ReadString();
                            Console.WriteLine(name);
                            break;

                        case "Code":
                            string Code = reader.ReadString();
                            Console.WriteLine(Code);
                            break;

                        case "Credits":

                            break;


                    }
                }
            }
        }
    }

This is my code.

Thanks.

Answer 1

The problem with your current code is that the switch is only reached when reader.Name is "Modules4" , never one of its children.

If I were you I'd use the ReadSubtree() method:

...
if (reader.IsStartElement())
{
    if (reader.Name == "Modules4") 
    {
        ReadModules4(reader.ReadSubtree());
    }
}
...

Then you can process the subtree in a separate method:

void ReadModules4(XmlReader reader)
{
    while (reader.Read())
    {
        switch (reader.Name)
        {
            ...
        }
    }
}

Answer 2

I like using combination of xml reader and xml linq

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

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        static void Main(string[] args)
        {
            XmlReader reader = XmlReader.Create(FILENAME);

            reader.ReadToFollowing("Modules4");
            XmlReader module4Subtree = reader.ReadSubtree();
            while (!module4Subtree.EOF)
            {
                if (module4Subtree.Name != "Module")
                {
                    module4Subtree.ReadToFollowing("Module");
                }
                if (!module4Subtree.EOF)
                {
                    XElement module = (XElement)XElement.ReadFrom(module4Subtree);
                    Module.modules.Add(new Module() { name = (string)module.Element("Name"), code = (string)module.Element("Code"), credits = (int)module.Element("Credits") });
                }

            }
        }
    }
    public class Module
    {
        public static List<Module> modules = new List<Module>();

        public string name { get; set; }
        public string code { get; set; }
        public int credits { get; set; }
    }
}

Answer 3

Assume that in our example we have a xml with root node Reports and there are nested child nodes Reports and we need to loop through each child

sample.xml

 <?xml version="1.0" encoding="utf-8" ?> <Reports> <Report> <Code>CP</Code> <RepeatStyle>Weekly</RepeatStyle> </Report> <Report> <Code>USS</Code> <Name>User Snapshot</Name> <RepeatStyle>Monthly</RepeatStyle> </Report> <Report> <Code>USS</Code> <Name>Failed Logon Report</Name> <RepeatStyle>Monthly</RepeatStyle> </Report> <Report> <Code>USS</Code> <Name>Failed Logon Report</Name> <RepeatStyle>Monthly</RepeatStyle> </Report> </Reports> 

Here we can make use of System.Xml.XmlDocument which we used to read the Xml file given in the target location and System.Xml.XmlNodeList to pick up the certain nodes

XmlDocument serverDoc = new XmlDocument();
serverDoc.Load("sample.xml");
XmlNodeList xml = serverDoc.SelectNodes("Reports/Report");

foreach (XmlNode node in xml)
{
      var code = node.SelectSingleNode("Code").InnerText;
      var repeatStyle = node.SelectSingleNode("RepeatStyle").InnerText;
}