我如何提取信息内心深处使用C＃和LINQ XML？ [英] How do I extract info deep inside XML using C# and LINQ?
问题描述
这是我对计算器的第一篇文章，所以请大家多多包涵。我前期道歉，如果我的code的例子是有点长。
This is my first post on StackOverflow, so please bear with me. And I apologize upfront if my code example is a bit long.
使用C＃和LINQ，我试图找出一系列的第三级 ID 元素（在这种情况下，000049）在一个更大的XML文件。每一个第三级 ID 是独一无二的，和那些我想是基于一系列的每一个后代的信息。更具体地说，如果键入== A 和位置类型（老）==库和位置类型（新）==出，那么我想选择 ID 。下面是XML和C＃code，我使用。
Using C# and LINQ, I'm trying to identify a series of third level id elements (000049 in this case) in a much larger XML file. Each third level id is unique, and the ones I want are based on a series of descendant info for each. More specifically, if type == A and location type(old) == vault and location type(new) == out, then I want to select that id. Below is the XML and C# code that I'm using.
在一般我code ++工程。请按照如下步骤将返回000049的 ID 的两倍，这是正确的。不过，我已经找到了故障。如果删除第一个历史块，其中包含类型== A ，我的code仍然会返回一个 ID 的000049次时，只应该再返回。我知道为什么会发生，但我想不出更好的方式来运行查询。有没有更好的方式来运行我的查询来得到我想要的输出，并仍然使用LINQ？
In general my code works. As written below it will return an id of 000049 twice, which is correct. However, I have found a glitch. If I remove the first history block that contains type == A, my code still returns an id of 000049 twice when it should only return it once. I know why it is happening, but I can't figure out a better way to run the query. Is there a better way to run my query to get the output I want and still use LINQ?
我的XML：
<?xml version="1.0" encoding="ISO8859-1" ?>
<data type="historylist">
<date type="runtime">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
<hour>15</hour>
<minutes>24</minutes>
<seconds>46</seconds>
</date>
<customer>
<id>0001</id>
<description>customer</description>
<mediatype>
<id>kit</id>
<description>customer kit</description>
<volume>
<id>000049</id>
<history>
<date type="optime">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
<hour>03</hour>
<minutes>00</minutes>
<seconds>02</seconds>
</date>
<userid>batch</userid>
<type>OD</type>
<location type="old">
<repository>vault</repository>
<slot>0</slot>
</location>
<location type="new">
<repository>out</repository>
<slot>0</slot>
</location>
<container>0001.kit.000049</container>
<date type="movedate">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
</date>
</history>
<history>
<date type="optime">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
<hour>06</hour>
<minutes>43</minutes>
<seconds>33</seconds>
</date>
<userid>vaultred</userid>
<type>A</type>
<location type="old">
<repository>vault</repository>
<slot>0</slot>
</location>
<location type="new">
<repository>out</repository>
<slot>0</slot>
</location>
<container>0001.kit.000049</container>
<date type="movedate">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
</date>
</history>
<history>
<date type="optime">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
<hour>06</hour>
<minutes>43</minutes>
<seconds>33</seconds>
</date>
<userid>vaultred</userid>
<type>S</type>
<location type="old">
<repository>vault</repository>
<slot>0</slot>
</location>
<location type="new">
<repository>out</repository>
<slot>0</slot>
</location>
<container>0001.kit.000049</container>
<date type="movedate">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
</date>
</history>
<history>
<date type="optime">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
<hour>06</hour>
<minutes>45</minutes>
<seconds>00</seconds>
</date>
<userid>batch</userid>
<type>O</type>
<location type="old">
<repository>out</repository>
<slot>0</slot>
</location>
<location type="new">
<repository>site</repository>
<slot>0</slot>
</location>
<container>0001.kit.000049</container>
<date type="movedate">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
</date>
</history>
<history>
<date type="optime">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
<hour>11</hour>
<minutes>25</minutes>
<seconds>59</seconds>
</date>
<userid>ihcmdm</userid>
<type>A</type>
<location type="old">
<repository>out</repository>
<slot>0</slot>
</location>
<location type="new">
<repository>site</repository>
<slot>0</slot>
</location>
<container>0001.kit.000049</container>
<date type="movedate">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
</date>
</history>
<history>
<date type="optime">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
<hour>11</hour>
<minutes>25</minutes>
<seconds>59</seconds>
</date>
<userid>ihcmdm</userid>
<type>S</type>
<location type="old">
<repository>out</repository>
<slot>0</slot>
</location>
<location type="new">
<repository>site</repository>
<slot>0</slot>
</location>
<container>0001.kit.000049</container>
<date type="movedate">
<year>2011</year>
<month>04</month>
<day>22</day>
<dayname>Friday</dayname>
</date>
</history>
</volume>
...
我的C＃code：
My C# code:
IEnumerable<XElement> caseIdLeavingVault =
from volume in root.Descendants("volume")
where
(from type in volume.Descendants("type")
where type.Value == "A"
select type).Any() &&
(from locationOld in volume.Descendants("location")
where
((String)locationOld.Attribute("type") == "old" &&
(String)locationOld.Element("repository") == "vault") &&
(from locationNew in volume.Descendants("location")
where
((String)locationNew.Attribute("type") == "new" &&
(String)locationNew.Element("repository") == "out")
select locationNew).Any()
select locationOld).Any()
select volume.Element("id");
...
foreach (XElement volume in caseIdLeavingVault)
{
Console.WriteLine(volume.Value.ToString());
}
感谢。
确定家伙，我又难住了。鉴于此相同的情况，并@以下（这伟大工程），我需要的optime和movedate日期为历史用来选择 ID 。那有意义吗？我希望结束与这样的：
OK guys, I'm stumped again. Given this same situation and @Elian's solution below (which works great), I need the "optime" and "movedate" dates for the history used to select the id. Does that make sense? I was hoping to end with something like this:
select new {
id = volume.Element("id").Value,
// this is from "optime"
opYear = <whaterver>("year").Value,
opMonth = <whatever>("month").Value,
opDay = <whatever>("day").Value,
// this is from "movedate"
mvYear = <whaterver>("year").Value,
mvMonth = <whatever>("month").Value,
mvDay = <whatever>("day").Value
}
我已经尝试了许多不同的组合，但属性 S表示＆LT;日期类型=optime＆GT; 和＆LT;日期类型=movedate＆GT; 继续得到我的路，我似乎无法得到我想要
I have tried so many different combinations, but the Attributes for <date type="optime"> and <date type="movedate"> keep getting in my way and I can't seem to get what I want.
确定。我发现了一个<一个href="http://stackoverflow.com/questions/2489433/linq-to-xml-query-to-select-specific-sub-element-based-on-additional-criteria">solution行之有效：
OK. I found a solution that works well:
select new {
caseId = volume.Element("id").Value,
// this is from "optime"
opYear = volume.Descendants("date").Where(t => t.Attribute("type").Value == "optime").First().Element("year").Value,
opMonth = volume.Descendants("date").Where(t => t.Attribute("type").Value == "optime").First().Element("month").Value,
opDay = volume.Descendants("date").Where(t => t.Attribute("type").Value == "optime").First().Element("day").Value,
// this is from "movedate"
mvYear = volume.Descendants("date").Where(t => t.Attribute("type").Value == "movedate").First().Element("year").Value,
mvMonth = volume.Descendants("date").Where(t => t.Attribute("type").Value == "movedate").First().Element("month").Value,
mvDay = volume.Descendants("date").Where(t => t.Attribute("type").Value == "movedate").First().Element("day").Value
};
然而，它并当它发现一个 ID 没有movedate失败。其中的几个存在的，所以现在我的工作的。
However, it does fail when it finds an id with no "movedate". A few of these exist, so now I am working on that.
嗯，昨天下午我终于想通了解决方案，我一直想：
Well, late yesterday afternoon I finally figured out the solution I had been wanting:
var caseIdLeavingSite =
from volume in root.Descendants("volume")
where volume.Elements("history").Any(
h => h.Element("type").Value == "A" &&
h.Elements("location").Any(l => l.Attribute("type").Value == "old" && ((l.Element("repository").Value == "site") ||
(l.Element("repository").Value == "init"))) &&
h.Elements("location").Any(l => l.Attribute("type").Value == "new" && l.Element("repository").Value == "toVault")
)
select new {
caseId = volume.Element("id").Value,
opYear = volume.Descendants("date").Where(t => t.Attribute("type").Value == "optime").First().Element("year").Value,
opMonth = volume.Descendants("date").Where(t => t.Attribute("type").Value == "optime").First().Element("month").Value,
opDay = volume.Descendants("date").Where(t => t.Attribute("type").Value == "optime").First().Element("day").Value,
mvYear = (volume.Descendants("date").Where(t => t.Attribute("type").Value == "movedate").Any() == true) ?
(volume.Descendants("date").Where(t => t.Attribute("type").Value == "movedate").First().Element("year").Value) : "0",
mvMonth = (volume.Descendants("date").Where(t => t.Attribute("type").Value == "movedate").Any() == true) ?
(volume.Descendants("date").Where(t => t.Attribute("type").Value == "movedate").First().Element("month").Value) : "0",
mvDay = (volume.Descendants("date").Where(t => t.Attribute("type").Value == "movedate").Any() == true) ?
(volume.Descendants("date").Where(t => t.Attribute("type").Value == "movedate").First().Element("day").Value) : "0"
};
这满足了@Elian帮助的要求，并抓住必要的额外的最新信息。这也解释了那些少数情况时，有一个没有元素movedate通过使用三元运算符：。
This satisfies the requirements that @Elian helped with and grabs the additional date info necessary. It also accounts for those few instances when there is no element for "movedate" by using the ternary operator ?:.
现在，如果有人知道如何让这种更有效的，我仍然有兴趣。谢谢你。
Now, if anyone knows how to make this more efficient, I'm still interested. Thanks.
推荐答案
我想你想是这样的：
IEnumerable<XElement> caseIdLeavingVault =
from volume in document.Descendants("volume")
where volume.Elements("history").Any(
h => h.Element("type").Value == "A" &&
h.Elements("location").Any(l => l.Attribute("type").Value == "old" && l.Element("repository").Value == "vault") &&
h.Elements("location").Any(l => l.Attribute("type").Value == "new" && l.Element("repository").Value == "out")
)
select volume.Element("id");
您code独立检查，如果卷有一个＆LT;历史＆GT; 类型的元素 A 和一个（不一定是相同的）＆LT;历史＆GT; 元素，它具有所需的＆LT;地点＆gt; 元素。
Your code independently checks if a volume has a <history> element of type A and a (not necessarily the same) <history> element which has the required <location> elements.
在code以上检查，如果存在一个＆LT;历史＆GT; 元素，既类型的 A 和包含所需的＆LT;地点＆gt; 元素。
The code above checks if there exists a <history> element that is both of type A and contains the required <location> elements.
更新： Abatishchev建议使用XPath查询，而不是LINQ到XML，但他的问题是过于简单，不返回你问什么解决的办法。下面的XPath查询会做的伎俩，但它也是一点点长：
Update: Abatishchev suggested a solution that uses an xpath query instead of LINQ to XML, but his query is too simple and doesn't return exactly what you asked for. The following xpath query will do the trick, but it's also a little bit longer:
data/customer/mediatype/volume[history[type = 'A' and location[@type = 'old' and repository = 'vault'] and location[@type = 'new' and repository = 'out']]]/id
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