C# LINQ 读取 XML
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LINQ to read XML
提问by Aximili
I got this XML file:
我得到了这个 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>
Could someone give me a C# code using LINQ, the simplest way to print this result:
(Note the extra space if it is a level2node)
有人可以给我一个使用 LINQ 的 C# 代码，这是打印此结果的最简单方法：（
如果它是level2节点，请注意额外的空间）
A
A1
A2
B
B1
B2
C
Currently I got this code:
目前我得到了这个代码：
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...???
}
采纳答案by bendewey
Try this.
尝试这个。
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);
}
回答by eglasius
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. You have to use .Root on any of these versions.
附言。您必须在这些版本中的任何一个上使用 .Root。
回答by dommer
A couple of plain old foreachloops provides a clean solution:
几个普通的旧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);
}
}
回答by dommer
Or, if you want a more general approach - i.e. for nesting up to "levelN":
或者，如果您想要更通用的方法 - 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();
}
回答by delliottg
Here are a couple of complete working examples that build on the @bendewey & @dommer examples. I needed to tweak each one a bit to get it to work, but in case another LINQ noob is looking for working examples, here you go:
这里有几个完整的工作示例，它们构建在 @bendewey 和 @dimmer 示例之上。我需要稍微调整一下才能让它工作，但如果另一个 LINQ 菜鸟正在寻找工作示例，那么你去吧：
//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
}
}
And next:
接下来：
//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();
}
}
These both compile & work in VS2010 using csc.exe version 4.0.30319.1 and give the exact same output. Hopefully these help someone else who's looking for working examples of code.
这些都使用 csc.exe 版本 4.0.30319.1 在 VS2010 中编译和工作，并给出完全相同的输出。希望这些可以帮助正在寻找工作代码示例的其他人。
EDIT: added @eglasius' example as well since it became useful to me:
编辑：还添加了@eglasius 的示例，因为它对我有用：
//@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
}
}
