从类中的列表属性中删除元素

Question

在 C# System.Xml.Serialization 中有一个 XML 数据序列化。

有一个描述根元素的根类。它包含在后代类（如电影）中描述的 List 类型的文件。

我可以将我的 XML 文档反序列化为一个类，并简单地使用 List.Add 或 List.Insert 在列表中添加一个新元素：

cfg.Movies.Insert(0, new Movie("Newly added: Pulp Fiction", "1994"));

但是反向操作不起作用：

cfg.Movies.Remove(new Movie("To be removed: The Godfather", "1974"));

所以问题是如何从 xml 类列表中删除一个元素？

样本在这里：https://dotnetfiddle.net/WqCNoD

using System;
using System.IO;
using System.Xml;
using System.Xml.Linq;
using System.Collections.Generic;
using System.Xml.Serialization;

public class Program
{
public static void Main()
{

    string xmlString =
        @"<favorites>
                <movies>
                    <movie title=""To be removed: The Godfather"" year=""1974"" />
                    <movie title=""The Terminator"" year=""1984"" />
                    <movie title=""Dark Knight"" year=""2008"" />
                </movies>

                <books>
                    <book title = ""1984"" author=""George Orwell"" />
                    <book title = ""Robinson Crusoe"" author=""Daniel Defoe "" />
                    <book title = ""Frankenstein"" author=""Mary Shelly"" />
                </books>

                <music>
                    <artist title = ""Beatles"" genre=""rock"" />
                    <artist title = ""Queen"" genre=""rock"" />
                    <artist title = ""Metallica"" rock=""heavy metal"" />
                </music>
            </favorites>";

    XDocument xdoc = XDocument.Parse(xmlString);

    var xdocData = xdoc.ToString();

    //DeSerialization
    XmlSerializer serializer = new XmlSerializer(typeof(Favorites));
    using (StringReader reader = new StringReader(xdoc.ToString()))
    {
        Favorites cfg = (Favorites) serializer.Deserialize(reader);


        // Add & remove element
        cfg.Movies.Insert(0, new Movie("Newly added: Pulp Fiction", "1994"));
        cfg.Movies.Remove(new Movie("To be removed: The Godfather", "1974"));


        //Serialization
        XmlSerializer serializer2 = new XmlSerializer(cfg.GetType());

        using (StringWriter writer = new StringWriter())
        {
            serializer2.Serialize(writer, cfg);
            Console.WriteLine(writer.ToString());

        }

    }
}



[XmlRoot(ElementName = "favorites", DataType = "string", IsNullable = true)]
public class Favorites
{
    //public string Name { get; set; }

    [XmlArray("movies")]
    [XmlArrayItem("movie")]
    public List<Movie> Movies { get; set; }

    public Favorites()
    {
        Movies = new List<Movie>();
    }
}


public class Movie
{
    [XmlAttribute("title")]
    public string Title { get; set; }
    [XmlAttribute("year")]
    public string Year { get; set; }

    public Movie() { }

    public Movie(string title, string year)
    {
        Title = title;
        Year = year;
    }
  }
}

Answer 1

当您创建一个新对象时，它的引用还没有在列表中。您需要在列表中搜索要删除的项目，然后使用搜索结果将其删除。

类似：

var movieToRemove = cfg.Movies.SingleOrDefault(m => m.Title == "To be removed: The Godfather" && m.Year == "1974");
if (moveiToRemove != null)
  cfg.Movies.Remove(movieToRemove);

Answer 2

您正在尝试删除一部新电影，而不是您反序列化的电影。

您必须先在列表中找到该电影，然后再将其删除。

替换

cfg.Movies.Remove(new Movie("To be removed: The Godfather", "1974"));

有

cfg.Movies.Remove(cfg.Movies.Find(x => x.Title == "Newly added: Pulp Fiction"));