使用C＃中的LINQ根据值迭代xmldocument [英] Iterate through xmldocument depending on value using LINQ in C#

问题描述

嘿伙计们，

我有xml看起来像这样：

 <   Root  >  
 <  类别    TopCategory   =  txt 1    MediumCategory   =  txt 2    SubCategory   =  txt 3     /  >  
 <  类别    TopCategory   =  txt 4    MediumCategory   =  txt 4    SubCategory   =  txt 5    /  >  
 <  类别    TopCategory   =  txt 7    MediumCategory   =  txt 8    SubCategory   =  txt 9    /   >  
 <  类别    TopCategory   =  txt 10    MediumCategory   =  txt 11    SubCategory   =  txt 12    /  >  
 <  类别    TopCategory   =  txt 13    MediumCategory   =  txt 14    SubCategory   =  txt 15    /  >  
 <  类别    TopCategory   =  txt 16    MediumCategory   =  txt 17    SubCategory   =  txt 18    /  >  
 <   / Root  >  

现在，xml传递给XmlDocument对象，我想要的是提取TopCategory& MediumCategory仅使用LINQ的SubCategory==txt 12（例如）的值。

任何想法？请帮忙......



我尝试过的事情：



.................................................. .....

解决方案

本网站将向您展示如何：带有示例的LINQ to XML教程| DotNetCurry [ ^ ] - 参见第5点。如何使用LINQ to XML访问具有特定属性的特定元素 - 易于适应您的要求

作为解决方案1的替代方法< a href =https://www.codeproject.com/script/Membership/View.aspx?mid=1315955> Graeme_Grant [ ^ ]，我想说...



MSDN文档非常好。我建议首先：

LINQ to XML Overview（C＃） [ ^ ]

LINQ to XML（C＃） [ ^ ]

基本查询（LINQ to XML）（C＃） [ ^ ]，尤其是：如何：查找具有特定属性的元素（C＃） [ ^ ]



我会以这种方式解决您的问题：

  string  xcontent =  @ < ;根和GT; 
< Categories TopCategory ='txt 1'MediumCategory ='txt 2'SubCategory ='txt 3'/> 
< Categories TopCategory ='txt 4'MediumCategory ='txt 4'SubCategory ='txt 5'/> 
< Categories TopCategory ='txt 7'MediumCategory ='txt 8'SubCategory ='txt 9'/> 
< Categories TopCategory ='txt 10'MediumCategory ='txt 11'SubCategory ='txt 12'/> 
< Categories TopCategory ='txt 13'MediumCategory ='txt 14'SubCategory ='txt 15'/> 
< Categories TopCategory ='txt 16'MediumCategory ='txt 17'SubCategory ='txt 18'/> 
< / Root>; 
 
 XmlReader rdr = XmlReader.Create（ new  StringReader（xcontent）） ; 
 XDocument xdoc = XDocument.Load（rdr）; 
 
  var  result = xdoc.Descendants（）
。 Where（x = > （ string ）x.Attribute（  SubCategory）==   txt 12）; 

以上代码应返回（ IEnumerable< XElement> ）：

< Categories TopCategory =txt 10MediumCategory =txt 11SubCategory =txt 12/> 

Hey guys,
I have xml looks like that:

<Root>
  <Categories TopCategory="txt 1" MediumCategory="txt 2" SubCategory="txt 3" />
  <Categories TopCategory="txt 4" MediumCategory="txt 4" SubCategory="txt 5" />
  <Categories TopCategory="txt 7" MediumCategory="txt 8" SubCategory="txt 9" />
  <Categories TopCategory="txt 10" MediumCategory="txt 11" SubCategory="txt 12" />
  <Categories TopCategory="txt 13" MediumCategory="txt 14" SubCategory="txt 15" />
  <Categories TopCategory="txt 16" MediumCategory="txt 17" SubCategory="txt 18" />
</Root>

Now, the xml is passing to an XmlDocument object and what i want is extracting "TopCategory" & "MediumCategory" only where the value of "SubCategory" == "txt 12" (for example) using LINQ.
Any Ideas? please help....

What I have tried:

.......................................................

解决方案

This website will show you how: LINQ To XML Tutorials with Examples | DotNetCurry[^] - see point 5. "How Do I access Specific Element having a Specific Attribute using LINQ to XML" - easy to adapt to your requirements

As an alternative to solution 1 by Graeme_Grant[^], i'd like to say...

MSDN documentation is very good. I'd suggest to start with:
LINQ to XML Overview (C#)[^]
LINQ to XML (C#)[^]
Basic Queries (LINQ to XML) (C#)[^], especially: How to: Find an Element with a Specific Attribute (C#)[^]

I'd resolve your issue this way:

string xcontent = @"<Root>
  <Categories TopCategory='txt 1' MediumCategory='txt 2' SubCategory='txt 3' />
  <Categories TopCategory='txt 4' MediumCategory='txt 4' SubCategory='txt 5' />
  <Categories TopCategory='txt 7' MediumCategory='txt 8' SubCategory='txt 9' />
  <Categories TopCategory='txt 10' MediumCategory='txt 11' SubCategory='txt 12' />
  <Categories TopCategory='txt 13' MediumCategory='txt 14' SubCategory='txt 15' />
  <Categories TopCategory='txt 16' MediumCategory='txt 17' SubCategory='txt 18' />
</Root>";

XmlReader rdr = XmlReader.Create(new StringReader(xcontent));
XDocument xdoc = XDocument.Load(rdr);

var result = xdoc.Descendants()
		.Where(x=>(string)x.Attribute("SubCategory")=="txt 12");

Above code should return (IEnumerable<XElement>):

<Categories TopCategory="txt 10" MediumCategory="txt 11" SubCategory="txt 12" />

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