在这种情况下我会如何使用LINQ2XML？

Question

我有我的LINQ2XML查询工作的一半我的目标：

var XMLDoc = XDocument.Load("WeatherData.xml"); 

var maximums = from tempvalue in 
        XMLDoc.Descendants("temperature").Elements("value") 
       where tempvalue.Parent.Attribute("type").Value == "maximum" 
       select (string)tempvalue; 

var minimums = from tempvalue in 
        XMLDoc.Descendants("temperature").Elements("value") 
       where tempvalue.Parent.Attribute("type").Value == "minimum" 
       select (string)tempvalue; 

List<string> MaxTemps = maximums.ToList(); 
List<string> MinTemps = minimums.ToList(); 

不过，我在与正从XML文档的时间信息的麻烦，因为我有相匹配的布局关键信息（见XML注释），我想知道这将是在LINQ最好的解决办法与我现有的查询来参加这次数据：

（顺便说一句，这个XML数据来自web服务）

<?xml version="1.0" encoding="utf-8"?> 
<dwml> 
    <data> 
    <time-layout> 
     <!--  Maximums Key   --> 
     <layout-key>k-p24h-n7-1</layout-key> 
     <start-valid-time>2009-02-09T07:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-09T19:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-10T07:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-10T19:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-11T07:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-11T19:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-12T07:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-12T19:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-13T07:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-13T19:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-14T07:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-14T19:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-15T07:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-15T19:00:00-05:00</end-valid-time> 
    </time-layout> 
    <time-layout> 
     <!--  Minimums Key   --> 
     <layout-key>k-p24h-n7-2</layout-key> 
     <start-valid-time>2009-02-08T19:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-09T08:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-09T19:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-10T08:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-10T19:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-11T08:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-11T19:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-12T08:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-12T19:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-13T08:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-13T19:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-14T08:00:00-05:00</end-valid-time> 
     <start-valid-time>2009-02-14T19:00:00-05:00</start-valid-time> 
     <end-valid-time>2009-02-15T08:00:00-05:00</end-valid-time> 
    </time-layout> 
    <parameters> 
     <!--          1st Key --> 
     <temperature type="maximum" time-layout="k-p24h-n7-1"> 
     <value>44</value> 
     <value>57</value> 
     <value>55</value> 
     <value>40</value> 
     <value>39</value> 
     <value>34</value> 
     <value>33</value> 
     </temperature> 
     <!--          2nd Key --> 
     <temperature type="minimum" time-layout="k-p24h-n7-2"> 
     <value>24</value> 
     <value>38</value> 
     <value>46</value> 
     <value>35</value> 
     <value>25</value> 
     <value>27</value> 
     <value>23</value> 
     </temperature> 
    </parameters> 
    </data> 
</dwml> 

Answer 1

我会先把它分解成小块。首先，我会按摩的时间布局成一个更可行的形式，由布局键进行了分组，以相互关联的有效开始时间和有效终止时间：

var timeLayouts = 
    from tempvalue in XMLDoc.Descendants("time-layout") 
    let tempStartTimes = tempvalue.Elements("start-valid-time"). 
      Select((x, i) => new { Index = i, ValidDateTime = (DateTime)x }) 
    let tempEndTimes = tempvalue.Elements("end-valid-time"). 
      Select((x, i) => new { Index = i, ValidDateTime = (DateTime)x }) 
    select new 
    { 
     LayoutKey = tempvalue.Element("layout-key").Value, 
     ValidTimeRanges = 
      from s in tempStartTimes 
      from e in tempEndTimes 
      where s.Index == e.Index 
      select new 
      { 
       Index = s.Index, 
       ValidStartDateTime = s.ValidDateTime, 
       ValidEndDateTime = e.ValidDateTime 
      } 
    }; 

然后，我会按摩的许多参数以同样的方式：

var parameters = 
    from tempvalue in XMLDoc.Descendants("temperature") 
    select new 
    { 
     TemperatureType = (string) tempvalue.Attribute("type"), 
     TimeLayout = (string) tempvalue.Attribute("time-layout"), 
     Temperatures = tempvalue.Elements("value").Select((x, i) => 
      new { Index = i, Temperature = (int)x }) 
    }; 

从那里，它不是那么难，让您的最大值和最小值：

var maximums = 
    from p in parameters 
    where p.TemperatureType == "maximum" 
    from tl in timeLayouts 
    where tl.LayoutKey == p.TimeLayout 
    from tr in tl.ValidTimeRanges 
    from t in p.Temperatures 
    where tr.Index == t.Index 
    select new { tr.ValidStartDateTime, tr.ValidEndDateTime, 
     t.Temperature }; 

var minimums = 
    from p in parameters 
    where p.TemperatureType == "minimum" 
    from tl in timeLayouts 
    where tl.LayoutKey == p.TimeLayout 
    from tr in tl.ValidTimeRanges 
    from t in p.Temperatures 
    where tr.Index == t.Index 
    select new { tr.ValidStartDateTime, tr.ValidEndDateTime, 
     t.Temperature }; 

你可以去这个其他一些方法，如果你想简化例如，某些表示（例如，可以将布局和参数展平为更多“表格”），则只需进行一些调整即可。