C# 基于不同属性的嵌套LINQ到XML

我正在尝试编写一个嵌套查询，因为我正在处理的XML文档有多个子元素。 我需要访问文档id属性为“docdb”的值。 我需要访问文档id属性为“epodoc”的值

我的课堂案例定义如下：

public class case_
{
public string appNumber { get; set; }
public string appDate { get; set; }
}

<exchange-document system="ops.epo.org" family-id="8487663" country="EP" doc- number="0173444" kind="A1">
<bibliographic-data>
<publication-reference>
  <document-id document-id-type="docdb">
    <country>EP</country>
    <doc-number>0173444</doc-number>
    <kind>A1</kind>
    <date>19860305</date>
  </document-id>
  <document-id document-id-type="epodoc">
    <doc-number>EP0173444</doc-number>
    <date>19860305</date>
  </document-id>
</publication-reference>
<classification-ipc>
  <text>B27M3/06</text>
</classification-ipc>
<classifications-ipcr>
  <classification-ipcr sequence="1">
    <text>B27M   1/    04            A I                    </text>
  </classification-ipcr>
  <classification-ipcr sequence="2">
    <text>B27M   3/    04            A I                    </text>
  </classification-ipcr>
  <classification-ipcr sequence="3">
    <text>B44C   3/    12            A I                    </text>
  </classification-ipcr>
</classifications-ipcr>
<patent-classifications>
  <patent-classification sequence="1">
    <classification-scheme office="" scheme="CPC" />
    <section>B</section>
    <class>44</class>
    <subclass>C</subclass>
    <main-group>3</main-group>
    <subgroup>12</subgroup>
    <classification-value>I</classification-value>
  </patent-classification>
  <patent-classification sequence="2">
    <classification-scheme office="" scheme="CPC" />
    <section>B</section>
    <class>27</class>
    <subclass>M</subclass>
    <main-group>1</main-group>
    <subgroup>04</subgroup>
    <classification-value>I</classification-value>
  </patent-classification>
  <patent-classification sequence="3">
    <classification-scheme office="" scheme="CPC" />
    <section>B</section>
    <class>27</class>
    <subclass>M</subclass>
    <main-group>3</main-group>
    <subgroup>04</subgroup>
    <classification-value>I</classification-value>
  </patent-classification>
</patent-classifications>
<application-reference doc-id="16601238">
  <document-id document-id-type="docdb">
    <country>EP</country>
    <doc-number>85305178</doc-number>
    <kind>A</kind>
  </document-id>
  <document-id document-id-type="epodoc">
    <doc-number>EP19850305178</doc-number>
    <date>19850719</date>
  </document-id>
  <document-id document-id-type="original">
    <doc-number>85305178</doc-number>
  </document-id>
</application-reference>

以下是我到目前为止的情况：

var myCase = from theCases in allCasesXML.Descendants("exchange-document")
select new case_
{
appNumber = (string)theCases.Element("bibliographic-data").Element("application-reference").Element("document-id").Element("doc-number"),
appDate = (from p in theCases.Descendants("document-id")
where (string)theCases.Element("bibliographic-data").Element("application-reference").Element("document-id").Attribute("document-id-type") == "epodoc"
select (p.Element("date").Value)),

  };

        foreach (var case_ in myCase)
        {
            System.Windows.Forms.MessageBox.Show(case_.appDate.ToString());
        }

我正在使用的XML如下所示：

public class case_
{
public string appNumber { get; set; }
public string appDate { get; set; }
}

<exchange-document system="ops.epo.org" family-id="8487663" country="EP" doc- number="0173444" kind="A1">
<bibliographic-data>
<publication-reference>
  <document-id document-id-type="docdb">
    <country>EP</country>
    <doc-number>0173444</doc-number>
    <kind>A1</kind>
    <date>19860305</date>
  </document-id>
  <document-id document-id-type="epodoc">
    <doc-number>EP0173444</doc-number>
    <date>19860305</date>
  </document-id>
</publication-reference>
<classification-ipc>
  <text>B27M3/06</text>
</classification-ipc>
<classifications-ipcr>
  <classification-ipcr sequence="1">
    <text>B27M   1/    04            A I                    </text>
  </classification-ipcr>
  <classification-ipcr sequence="2">
    <text>B27M   3/    04            A I                    </text>
  </classification-ipcr>
  <classification-ipcr sequence="3">
    <text>B44C   3/    12            A I                    </text>
  </classification-ipcr>
</classifications-ipcr>
<patent-classifications>
  <patent-classification sequence="1">
    <classification-scheme office="" scheme="CPC" />
    <section>B</section>
    <class>44</class>
    <subclass>C</subclass>
    <main-group>3</main-group>
    <subgroup>12</subgroup>
    <classification-value>I</classification-value>
  </patent-classification>
  <patent-classification sequence="2">
    <classification-scheme office="" scheme="CPC" />
    <section>B</section>
    <class>27</class>
    <subclass>M</subclass>
    <main-group>1</main-group>
    <subgroup>04</subgroup>
    <classification-value>I</classification-value>
  </patent-classification>
  <patent-classification sequence="3">
    <classification-scheme office="" scheme="CPC" />
    <section>B</section>
    <class>27</class>
    <subclass>M</subclass>
    <main-group>3</main-group>
    <subgroup>04</subgroup>
    <classification-value>I</classification-value>
  </patent-classification>
</patent-classifications>
<application-reference doc-id="16601238">
  <document-id document-id-type="docdb">
    <country>EP</country>
    <doc-number>85305178</doc-number>
    <kind>A</kind>
  </document-id>
  <document-id document-id-type="epodoc">
    <doc-number>EP19850305178</doc-number>
    <date>19850719</date>
  </document-id>
  <document-id document-id-type="original">
    <doc-number>85305178</doc-number>
  </document-id>
</application-reference>

EP
0173444
A1
19860305
EP0173444
19860305
B27M3/06
B27M 1/04 A I
B27M 3/04 A I
B44C 3/12 A I
B
44
C
3.
12
我
B
27
M
1.
04
我
B
27
M
3.
04
我
EP
85305178
A.
EP19850305178
19850719
85305178

---

但是，我似乎无法获取查询以返回任何结果。

appDate

应与

appDate = (from p in theCases.Descendants("document-id")
where (string)p.Attribute("document-id-type") == "epodoc"
select (p.Element("date").Value)).FirstOrDefault()

---

根据Anirudh的帖子：

appDate = (from p in theCases.Descendants("application-reference").Descendants("document-  id") 
where (string)p.Attribute("document-id-type") == "epodoc" 
select (p.Element("date").Value)).FirstOrDefault()

Anirudh对post的更改是添加了另一个函数调用：

.Descendants("document-id") 

---

这是必需的，因为XML中有多个“文档id”元素。

谢谢。我稍微修改了一下：

appDate=（来自cases.substands（“应用程序引用”）.substands（“文档id”）

where（string）p.Attribute（“文档id类型”）==“epodoc”

选择（p.Element（“日期”）.Value））.FirstOrDefault（）