XML 文档中的特定元素

debugcn 发表于 Dev

托尼·基尔南

我有以下 XML：

<?xml version="1.0" encoding="utf-8" ?>
<catalog>
  <books>
<book id="bk101"> 
  <author id="1">Gambardella, Matthew</author>
  <title>XML Developer's Guide</title>
  <genre>Computer</genre>
  <cover-price>
    <price>
        <country>US</country>
        <amount>44.95</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>39.99</amount>
    </price>
  </cover-price>
  <unit-price>
    <price>
        <country>US</country>
        <amount>25.00</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>20.00</amount>
    </price>
  </unit-price>
  <publish_date>2000-10-01</publish_date>
   <description> An in-depth look at creating applications with XML.</description>
</book>
<book id="bk102">
  <author id="2">Ralls, Kim</author>
  <title>Midnight Rain</title>
  <genre>Fantasy</genre>
  <cover-price>
    <price>
        <country>US</country>
        <amount>5.95</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>3.99</amount>
    </price>
  </cover-price>
  <unit-price>
    <price>
        <country>US</country>
        <amount>2.50</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>2.00</amount>
    </price>
  </unit-price>
  <publish_date>2000-12-16</publish_date>
  <description> A former architect battles corporate zombies,an evil sorceress, and her own childhood to become
queen of the world.</description>
</book>
<book id="bk103">
  <author id="3">Corets, Eva</author>
  <title>Maeve Ascendant</title>
  <genre>Fantasy</genre>
  <cover-price>
    <price>
        <country>US</country>
        <amount>5.95</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>3.99</amount>
    </price>
  </cover-price>
  <unit-price>
    <price>
        <country>US</country>
        <amount>2.50</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>2.00</amount>
    </price>
  </unit-price>
    <publish_date>2000-11-17</publish_date>
    <description>After the collapse of a nanotechnology society in England, the young survivors lay the foundation for
a new society. </description>
  </book>

<book id="bk104">
    <author id="4">Corets, Eva</author>
    <title>Oberon's Legacy</title>
    <genre>Fantasy</genre>
  <cover-price>
    <price>
        <country>US</country>
        <amount>5.95</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>3.99</amount>
    </price>
  </cover-price>
  <unit-price>
    <price>
        <country>US</country>
        <amount>2.50</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>2.00</amount>
    </price>
  </unit-price>
    <publish_date>2001-03-10</publish_date>
    <description>In post-apocalypse England, the mysterious agent known only as Oberon helps to create a new life for
 the inhabitants of London. Sequel to Maeve Ascendant.</description>

  </book>

<book id="bk105">
    <author id="5">Corets, Eva</author>
    <title>The Sundered Grail</title>
    <genre>Fantasy</genre>
  <cover-price>
    <price>
        <country>US</country>
        <amount>5.95</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>3.99</amount>
    </price>
  </cover-price>
  <unit-price>
    <price>
        <country>US</country>
        <amount>2.50</amount>
    </price>
    <price>
        <country>UK</country>
        <amount>2.00</amount>
    </price>
  </unit-price>
    <publish_date>2001-09-10</publish_date>
    <description>The two daughters of Maeve, half-sisters, battle one another for control of England. Sequel to
Oberon's Legacy.</description>

  </book>
  </books>
</catalog>

我可以使用以下来选择特定的书

var selectedBook = from r in document.Descendants("book").Where
                                   (r=>(string)r.Attribute("id")=="bk102")
                        select new
                        {
                            Author = r.Element("author").Value,
                            Title = r.Element("title").Value,
                            Genere = r.Element("genre").Value,
                            Price = r.Element("price").Value,
                            PublishDate = r.Element("publish_date").Value,
                            Description = r.Element("description").Value,

                        };

然后我如何选择该书在美国的封面价格？我尝试过的每个组合都只返回所有四个金额字段

查克·萨维奇

你很近

var selectedBook = from r in document.Descendants("book").Where
                                   (r=>(string)r.Attribute("id")=="bk102")
                        select new
                        {
                            Author = r.Element("author").Value,
                            Title = r.Element("title").Value,
                            Genere = r.Element("genre").Value,
                            Price = r.Element("price").Value,
                            PublishDate = r.Element("publish_date").Value,
                            Description = r.Element("description").Value,
                            USPrice = r.Element("cover-price") 
                                       .Descendants("country")
                                       .Where(c => (string)c == "US"))
                                       .Select(c => (decimal)c.Parent.Element("amount"))
                                       .First()
                        };

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