c# - Linq to XML 降序排序？

Question

我在使用 OrderByDescending 时遇到问题。它没有正确排序。我有一个如下所示的 XML 文件:

  <player id="3">
     <name>David, Backham</name>      
     <goals>155</goals>        
  </player>

我正在尝试显示 3 名进球最多的球员。

 XDocument doc = XDocument.Load("players.xml");

                                     /// .OrderByDescending(r => r.Attribute("goals"))
        var players = from r in doc.Descendants("player").OrderByDescending(r => r.Value)

                           select new
                           {
                               Name = r.Element("name").Value + "   ",
                               Goal = r.Element("goals").Value + "    ",

                           };


        foreach (var r in players)
        {              
            Console.WriteLine(r.Name + r.Goal);
        }

Answer 1

大概是这样的:

var players = 
    (from r in doc.Descendants("player")
     orderby int.Parse(r.Element("goals").Value) descending 
     select new
     {
         Name = r.Element("name").Value + "   ",
         Goal = r.Element("goals").Value + "    ",
     })
    .Take(3);

或者用流利的语法:

var players = doc.Descendants("player")
                 .OrderByDescending(r => int.Parse(r.Element("goals").Value))
                 .Select(r => new
                  {
                      Name = r.Element("name").Value + "   ",
                      Goal = r.Element("goals").Value + "    ",
                  })
                 .Take(3);

请注意，您需要将字符串值解析为整数以获得正确的排序顺序。

要过滤结果，您可以这样做:

var players = 
    (from r in doc.Descendants("player")
     where r.Element("name").Value.StartsWith("David")
     orderby int.Parse(r.Element("goals").Value) descending 
     select new
     {
         Name = r.Element("name").Value + "   ",
         Goal = r.Element("goals").Value + "    ",
     })
    .Take(3);

或者用流利的语法:

var players = doc.Descendants("player")
                 .Where(r => r.Element("name").Value.StartsWith("David"))
                 .OrderByDescending(r => int.Parse(r.Element("goals").Value))
                 .Select(r => new
                  {
                      Name = r.Element("name").Value + "   ",
                      Goal = r.Element("goals").Value + "    ",
                  })
                 .Take(3);