Linq到XML没有得到结果

本文关键字：结果 XML Linq | 更新日期: 2023-09-27 18:11:48

我正在使用linq-to-xml创建一个结构列表。

linq路径找不到概念元素。我已经尝试了各种各样的配方，在我放弃使用xpath之前，我希望有人能向我展示linq的方法。感谢

这是xml

<response xmlns="http://www.domain.com/api">
  <about>
    <requestId>E9B73CA1F16A670C966BE2BABD3B2B22</requestId>
    <docId>09E167D994E00B0F511781C40B85AEC3</docId>
    <systemType>concept</systemType>
    <configId>odp_2007_l1_1.7k</configId>
    <contentType>text/plain</contentType>
    <contentDigest>09E167D994E00B0F511781C40B85AEC3</contentDigest>
    <requestDate>2011-10-18T09:51:28+00:00</requestDate>
    <systemVersion>2.1</systemVersion>
  </about>
  <conceptExtractor>
    <conceptExtractorResponse>
      <concepts>
        <concept weight="0.010466908" label="hell"/>
      </concepts>
    </conceptExtractorResponse>
  </conceptExtractor>
</response>

这是我的

public struct conceptweight
{
    public string concept { get; set; }
    public string weight { get; set; }
}
List<conceptweight> list = (from c
  in d.Descendants("response")
      .Descendants("conceptExtractor")
      .Descendants("conceptExtractorResponse")
      .Descendants("concepts")
  select new conceptweight()
         {
           concept = c.Attribute("label").Value,
           weight = c.Attribute("weight").Value
         }).ToList();

Linq到XML没有得到结果

您忘记了名称空间，它默认在根元素中。试试这个：

// Note: names changed to follow conventions, and now a class
// rather than a struct. Mutable structs are evil.
public class ConceptWeight
{
    public string Concept { get; set; }
    // Type changed to reflect the natural data type
    public double Weight { get; set; }
}
XNamespace ns = "http://www.domain.com/api";
// No need to traverse the path all the way, unless there are other "concepts"
// elements you want to ignore. Note the use of ns here.
var list = d.Descendants(ns + "concepts")
            .Select(c => new ConceptWeight
                    {
                        Concept = (string) c.Attribute("label"),
                        Weight = (double) c.Attribute("weight"),
                    })
            .ToList();

我在这里没有使用查询表达式，因为它没有添加任何值——您只是在执行from x in y select z，它更简单地通过Select扩展方法来表达。

XNamespace n = "http://www.domain.com/api";
List<conceptweight> list = (from c in d.Elements(n + "response").Elements(n + "conceptExtractor").Elements(n + "conceptExtractorResponse").Elements(n + "concepts").Elements(n + "concept")
                            select new conceptweight
                            {
                                concept = c.Attribute("label").Value,
                                weight = c.Attribute("weight").Value
                            }).ToList();

您忘记了名称空间和最后一个元素(concept(。啊，如果您进行内联初始化，则不需要new conceptweight中的()括号。Ah和Descendants将遍历元素的所有"级别"。如果要"手动"遍历它，请使用Elements。

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