Question

有人可以帮我解决这个问题。我有一个Web应用程序，需要执行以下操作：如何获得性别为“男性”的所有人的年龄和2013年的日期

非常感谢你的帮助

我有这个XML：

<company>
  <department>
    <departmentname>Dep 1</departmentname>
    <people>
      <person>
        <name>Sean</name>
        <date>2011-10-10</date>
        <gender>male</gender>
        <age>40</age>
      </person>
      <person>
        <name>John</name>
        <date>2013-10-18</date>
        <gender>male</gender>
        <age>45</age>
      </person>
      <person>
        <name>Linda</name>
        <date>2012-09-10</date>
        <gender>female</gender>
        <age>42</age>
      </person>
      <person>
        <name>Bob</name>
        <date>2013-10-01</date>
        <gender>male</gender>
        <age>35</age>
      </person>
    </people>
  </department>
  <department>
    <departmentname>Dep 2</departmentname>
    <people>
      <person>
        <name>Art</name>
        <date>2012-09-10</date>
        <gender>male</gender>
        <age>38</age>
      </person>
      <person>
        <name>Christina</name>
        <date>2013-10-20</date>
        <gender>female</gender>
        <age>45</age>
      </person>
      <person>
        <name>Marie</name>
        <date>2011-09-10</date>
        <gender>female</gender>
        <age>49</age>
      </person>
    </people>
  </department>
</company>

这是我的c＃代码：

string year = "2013";

protected List<string> GetPersons(string year)
{
    XElement company= XElement.Load(Server.MapPath(XMLfil));

    var persons= (from a in company.Elements("department").Elements("people").Elements("person")
                  where (string)a.Element("gender").Value == 'male' && (string)a.Element("date").Value == STARTS WITH 2013
                  select (string)(a.Element("age"))).ToList<string>();
    return persons; 
}

Answer 1

string year = "2013";

protected List<string> GetPersons(string year)
{
    XElement company= XElement.Load(Server.MapPath(XMLfil));

    var persons= (from a in company.Elements("department").Elements("people").Elements("person")
                  where (string)a.Element("gender").Value == 'male' && (string)a.Element("datum").Value.StartsWith(year)
                  select (string)(a.Element("age"))).ToList<string>();
    return persons;
}

或者尝试使用DateTime.Parse并仅比较年份。例如，当xml中的日期格式发生变化时，这会更好。

Answer 2

from p in company.Descendants("person")
let date = (string)p.Element("date")
where (string)p.Element("gender") == "male" &&
      date != null && date.StartsWith(year) // pass year as a string
select (string)p.Element("age")

输出：

45
35

但我建议你创建接受整数值的方法（因此年份数是一个整数）并返回整数值列表（因为年龄是整数）。同时使用方法的自描述名称，显示您的意图：

protected List<int> GetMaleAges(int year)
{
    var company= XElement.Load(Server.MapPath(XMLfil));
    var ages = from p in company.Descendants("person")
               let date = (DateTime?)p.Element("date") // use DateTime
               where (string)p.Element("gender") == "male" &&
                     date.HasValue && date.Value.Year == year
               select (int)p.Element("age")

    return ages.ToList();
}

注意：您还可以将日期标记为DateTime值而不是字符串

from p in company.Descendants("person")
let date = (DateTime?)p.Element("date")
where (string)p.Element("gender") == "male" &&
       date.HasValue && date.Value.Year == year // pass year as integer
select (int)p.Element("age")

您也可以使用XPath（最简洁的解决方案）

string xpath = String.Format(
   "//person[gender='male' and date[starts-with(., '{0}')]]/age", year);
return company.XPathSelectElements(xpath).Select(a => (int)a);

Answer 3

您可以尝试使用“包含”（String.Contains）进行检查，以便日期格式发生变化时，您的查询也会有效。

var persons = (from a in company.Descendants("person")
                   where a.Element("gender").Value.ToLower() == "male" && a.Element("date").Value.Contains("2013")
                   select a.Element("age").Value).ToList<string>();

Answer 4

谢谢你们！我从未听说过StartsWith。现在感谢你了！

这是我的解决方案：

string year = "2013";

protected List<string> GetPersons(string year)
{
    XElement company= XElement.Load(Server.MapPath(XMLfil));

    var persons= (from a in company.Elements("department").Elements("people").Elements("person")
                  where (string)a.Element("gender").Value == 'male' && a.Element("date").Value.StartsWith(year)                      
                 select (string)(a.Element("age"))).ToList<string>();
    return persons; 
}

XML让日期从2013年开始的人们

4 个答案: