LINQ读取XML

我正在使用这个XML文件:

<root>
<level1 name="A">
<level2 name="A1" />
<level2 name="A2" />
</level1>
<level1 name="B">
<level2 name="B1" />
<level2 name="B2" />
</level1>
<level1 name="C" />
</root>
谁能给我一个使用LINQ的c#代码，最简单的方法来打印这个结果 (如果是level2节点，请注意额外的空格)

A
A1
A2
B
B1
B2
C

目前我已经写了这段代码:

XDocument xdoc = XDocument.Load("data.xml"));
var lv1s = from lv1 in xdoc.Descendants("level1")
select lv1.Attribute("name").Value;


foreach (var lv1 in lv1s)
{
result.AppendLine(lv1);
var lv2s = from lv2 in xdoc...???
}
435286 次浏览
小开
最佳答案

试试这个。

using System.Xml.Linq;


void Main()
{
StringBuilder result = new StringBuilder();


//Load xml
XDocument xdoc = XDocument.Load("data.xml");


//Run query
var lv1s = from lv1 in xdoc.Descendants("level1")
select new {
Header = lv1.Attribute("name").Value,
Children = lv1.Descendants("level2")
};


//Loop through results
foreach (var lv1 in lv1s){
result.AppendLine(lv1.Header);
foreach(var lv2 in lv1.Children)
result.AppendLine("     " + lv2.Attribute("name").Value);
}


Console.WriteLine(result);
}
小开 
XDocument xdoc = XDocument.Load("data.xml");
var lv1s = xdoc.Root.Descendants("level1");
var lvs = lv1s.SelectMany(l=>
new string[]{ l.Attribute("name").Value }
.Union(
l.Descendants("level2")
.Select(l2=>"   " + l2.Attribute("name").Value)
)
);
foreach (var lv in lvs)
{
result.AppendLine(lv);
}

Ps.你必须在这些版本中使用. root。

小开

几个普通的foreach循环提供了一个干净的解决方案:

foreach (XElement level1Element in XElement.Load("data.xml").Elements("level1"))
{
result.AppendLine(level1Element.Attribute("name").Value);


foreach (XElement level2Element in level1Element.Elements("level2"))
{
result.AppendLine("  " + level2Element.Attribute("name").Value);
}
}
小开

或者，如果你想要一个更通用的方法-即嵌套到“levelN”:

void Main()
{
XElement rootElement = XElement.Load(@"c:\events\test.xml");


Console.WriteLine(GetOutline(0, rootElement));
}


private string GetOutline(int indentLevel, XElement element)
{
StringBuilder result = new StringBuilder();


if (element.Attribute("name") != null)
{
result = result.AppendLine(new string(' ', indentLevel * 2) + element.Attribute("name").Value);
}


foreach (XElement childElement in element.Elements())
{
result.Append(GetOutline(indentLevel + 1, childElement));
}


return result.ToString();
}
小开

这里有几个完整的工作示例，建立在@bendewey &@dommer例子。我需要稍微调整每一个让它工作，但以防另一个LINQ新手正在寻找工作示例，这里:

//bendewey's example using data.xml from OP
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;


class loadXMLToLINQ1
{
static void Main( )
{
//Load xml
XDocument xdoc = XDocument.Load(@"c:\\data.xml"); //you'll have to edit your path


//Run query
var lv1s = from lv1 in xdoc.Descendants("level1")
select new
{
Header = lv1.Attribute("name").Value,
Children = lv1.Descendants("level2")
};


StringBuilder result = new StringBuilder(); //had to add this to make the result work
//Loop through results
foreach (var lv1 in lv1s)
{
result.AppendLine("  " + lv1.Header);
foreach(var lv2 in lv1.Children)
result.AppendLine("    " + lv2.Attribute("name").Value);
}
Console.WriteLine(result.ToString()); //added this so you could see the output on the console
}
}

和下一个:

//Dommer's example, using data.xml from OP
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;


class loadXMLToLINQ
{
static void Main( )
{
XElement rootElement = XElement.Load(@"c:\\data.xml"); //you'll have to edit your path
Console.WriteLine(GetOutline(0, rootElement));
}


static private string GetOutline(int indentLevel, XElement element)
{
StringBuilder result = new StringBuilder();
if (element.Attribute("name") != null)
{
result = result.AppendLine(new string(' ', indentLevel * 2) + element.Attribute("name").Value);
}
foreach (XElement childElement in element.Elements())
{
result.Append(GetOutline(indentLevel + 1, childElement));
}
return result.ToString();
}
}

它们都编译&使用csc.exe版本4.0.30319.1在VS2010中工作，并给出完全相同的输出。希望这些内容能够帮助其他正在寻找代码示例的人。

编辑:添加了@eglasius的例子，因为它对我很有用:

//@eglasius example, still using data.xml from OP
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;


class loadXMLToLINQ2
{
static void Main( )
{
StringBuilder result = new StringBuilder(); //needed for result below
XDocument xdoc = XDocument.Load(@"c:\\deg\\data.xml"); //you'll have to edit your path
var lv1s = xdoc.Root.Descendants("level1");
var lvs = lv1s.SelectMany(l=>
new string[]{ l.Attribute("name").Value }
.Union(
l.Descendants("level2")
.Select(l2=>"   " + l2.Attribute("name").Value)
)
);
foreach (var lv in lvs)
{
result.AppendLine(lv);
}
Console.WriteLine(result);//added this so you could see the result
}
}

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