如何更改我的 LINQ 查询以显示正确的 XML？答案

【问题标题】：How do i change my LINQ query to show the correct XML?如何更改我的 LINQ 查询以显示正确的 XML？
【发布时间】：2020-08-26 21:23:14
【问题描述】：

所以我无法打印正确的 XML。这个想法是从查询中创建一个 XML。

我有两节课；曲目和 CD。 Track 包含轨道的属性，CD 包含名称和艺术家属性以及 List

class Track
{
    public string Title { get; set; }
    public string Artist { get; set; }
    public TimeSpan Length { get; set; }

    public static List<Track> CreateTrackList()
    {
        List<Track> tracks = new List<Track>
        {
            new Track { Title = "Numb", Artist = "Linkin Park", Length = new TimeSpan(00, 03, 05)},
            new Track { Title = "Breaking the Habit", Artist = "Linkin Park", Length = new TimeSpan(00, 03, 16)},
            new Track { Title = "Faint", Artist = "Linkin Park", Length = new TimeSpan(00, 02, 42)}
        };
        return tracks;
    }

}

    class CD
{
    public string Artist { get; set; }
    public string Name { get; set; }
    public List<Track> Tracks { get; set; }

    public CD(string artist, string name, List<Track> tracks)
    {
        this.Artist = artist;
        this.Name = name;
        this.Tracks = tracks;
    }
}

        List<Track> tracks = Track.CreateTrackList();
        CD cd = new CD("Linkin Park", "Meteora", tracks);
        String xmlString;
        using (WebClient wc = new WebClient())
        {
            xmlString = wc.DownloadString(@"http://ws.audioscrobbler.com/2.0/?method=album.getinfo&api_key=b5cbf8dcef4c6acfc5698f8709841949&artist=Linkin+Park&album=Meteora");
        }
        XDocument myXMLDoc = XDocument.Parse(xmlString);

        IEnumerable<XElement> query1 = from track in myXMLDoc.Descendants("track")
                                       from t in cd.Tracks
                                       where track.Element("name").Value != t.Title && track.Element("artist").Element("name").Value == t.Artist
                                       select track;
        foreach (XElement t in query1)
        {
           Console.WriteLine(t);
        }

当我运行代码时，我得到以下 XML 输出：

<track rank="1">
  <name>Foreword</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Foreword</url>
  <duration>13</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="1">
  <name>Foreword</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Foreword</url>
  <duration>13</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="1">
  <name>Foreword</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Foreword</url>
  <duration>13</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="2">
  <name>Don't Stay</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Don%27t+Stay</url>
  <duration>188</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="2">
  <name>Don't Stay</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Don%27t+Stay</url>
  <duration>188</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="2">
  <name>Don't Stay</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Don%27t+Stay</url>
  <duration>188</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="3">
  <name>Somewhere I Belong</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Somewhere+I+Belong</url>
  <duration>214</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="3">
  <name>Somewhere I Belong</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Somewhere+I+Belong</url>
  <duration>214</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="3">
  <name>Somewhere I Belong</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Somewhere+I+Belong</url>
  <duration>214</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="4">
  <name>Lying from You</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Lying+from+You</url>
  <duration>175</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="4">
  <name>Lying from You</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Lying+from+You</url>
  <duration>175</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="4">
  <name>Lying from You</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Lying+from+You</url>
  <duration>175</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="5">
  <name>Hit the Floor</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Hit+the+Floor</url>
  <duration>164</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="5">
  <name>Hit the Floor</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Hit+the+Floor</url>
  <duration>164</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="5">
  <name>Hit the Floor</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Hit+the+Floor</url>
  <duration>164</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="6">
  <name>Easier to Run</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Easier+to+Run</url>
  <duration>204</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="6">
  <name>Easier to Run</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Easier+to+Run</url>
  <duration>204</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="6">
  <name>Easier to Run</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Easier+to+Run</url>
  <duration>204</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="7">
  <name>Faint</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Faint</url>
  <duration>162</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="7">
  <name>Faint</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Faint</url>
  <duration>162</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="8">
  <name>Figure.09</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Figure.09</url>
  <duration>197</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="8">
  <name>Figure.09</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Figure.09</url>
  <duration>197</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="8">
  <name>Figure.09</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Figure.09</url>
  <duration>197</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="9">
  <name>Breaking the Habit</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Breaking+the+Habit</url>
  <duration>196</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="9">
  <name>Breaking the Habit</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Breaking+the+Habit</url>
  <duration>196</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="10">
  <name>From the Inside</name>
  <url>https://www.last.fm/music/Linkin+Park/_/From+the+Inside</url>
  <duration>175</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="10">
  <name>From the Inside</name>
  <url>https://www.last.fm/music/Linkin+Park/_/From+the+Inside</url>
  <duration>175</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="10">
  <name>From the Inside</name>
  <url>https://www.last.fm/music/Linkin+Park/_/From+the+Inside</url>
  <duration>175</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="11">
  <name>Nobody's Listening</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Nobody%27s+Listening</url>
  <duration>178</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="11">
  <name>Nobody's Listening</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Nobody%27s+Listening</url>
  <duration>178</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="11">
  <name>Nobody's Listening</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Nobody%27s+Listening</url>
  <duration>178</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="12">
  <name>Session</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Session</url>
  <duration>144</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="12">
  <name>Session</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Session</url>
  <duration>144</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="12">
  <name>Session</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Session</url>
  <duration>144</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="13">
  <name>Numb</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Numb</url>
  <duration>188</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>
<track rank="13">
  <name>Numb</name>
  <url>https://www.last.fm/music/Linkin+Park/_/Numb</url>
  <duration>188</duration>
  <streamable fulltrack="0">0</streamable>
  <artist>
    <name>Linkin Park</name>
    <mbid>f59c5520-5f46-4d2c-b2c4-822eabf53419</mbid>
    <url>https://www.last.fm/music/Linkin+Park</url>
  </artist>
</track>

如您所见，它显示所有曲目 3 次，而 t.Title 中的曲目显示两次。我如何更改我的代码，以便它显示每首曲目一次，除了 t.Title 中的曲目？

【问题讨论】：

欢迎来到 Stack Overflow。请阅读the help pages，接受SO tour，阅读How to Ask，以及this question checklist。最后请在选择标签时小心，不要选择 e.g. C 语言标签而不是 C#。也请了解如何edit您的问题来解决问题。
当您执行 foreach（query1 中的 XElement t）时，您可能想要进行分组。见stackoverflow.com/questions/12097185/…
From : track.Element("name").Value != t.Title To : track.Element("name").Value == t.Title 您使用不等于而不是等于.

标签： c# xml linq

【解决方案1】：

您正在执行交叉连接，但根据描述，您似乎正在“where”中寻找简单的过滤，有人认为是这样的：

IEnumerable<XElement> query1 = from track in myXMLDoc.Descendants("track")
                               where !cd.Tracks.Any(an=>
                                        an.Title == track.Element("name").Value
                                        && track.Element("artist").Element("name").Value == an.Artist)
                                       select track;

【讨论】：

这很完美，也很完美。非常感谢！