从IEnumerable <IEnumerable <string >>转换为ICollection <T>

Question

我想要一个转换IEnumerable<IEnumerable<string>>到ICollection<Character>,但努力找出要做正确的方式,因为一个对象的结构比其他的结构不同.

转换的原因是采用json反序列化并通过Entity Framework将其插入到数据库中.json数据未规范化,与数据库的确切结构不匹配.在数据库中,我有a movie和a person具有多对多关系.它们之间的桥牌表是characters.但是json只有一个带有一组人物对象的电影对象,每个人都有一组他们扮演的角色(IEnumerable<IEnumerable<string>>).

基本上,我需要将每部电影的人物及其角色转换为每部电影的角色及其各自的人物.

var movie = dataContractMovies.Select(m => new Movie {
    Title = m.Title,
    // not sure how to convert each Person and their characters
    Characters = // Need to take each Person and their Characters in m.Cast and cast to a new Character and a new Person for which the Character belongs to
});

转换自

public class MovieDataContract {
    [DataMember(Name = "title")]
    public string Title { get; set; }

    [DataMember(Name = "abridged_cast")]
    public virtual IEnumerable<Person> Cast { get; set; }
}

[DataContract]
public class Person {
    [DataMember(Name = "name")]
    public string Name { get; set; }

    [DataMember(Name = "characters")]
    public IEnumerable<string> Characters { get; set; }
} 

转换成

public partial class Movie {
    public string Title { get; set; }
    public virtual ICollection<Character> Characters { get; set; }

    public Movie() {
        this.Characters = new HashSet<Character>();
    }
}

public partial class Character {
    public string Name { get; set; }
    public virtual Movie Movie { get; set; }
    public virtual Person Person { get; set; }
}

public partial class Person {
    public string Name { get; set; }
    public virtual ICollection<Character> Characters { get; set; }

    public Person() {
        this.Characters = new HashSet<Character>();
    }
}

更新和进一步的问题

如果我只是增加了一个public IEnumerable<Character> Characters到MovieDataContract？然后我可以做这样的事情(理论上,没有测试过)......

Characters = m.Characters;

所以我的新款MovieDataContract看起来像这样......

[DataContract]
public class MovieDataContract {
    [DataMember(Name = "title")]
    public string Title { get; set; }

    [DataMember(Name = "abridged_cast")]
    private IEnumerable<Person> _cast { get; set; }

    public IEnumerable<Character> Characters { 
        get{  
            foreach(var person in _cast) {
                foreach(string name in person.characters) {
                    yield return new Character { Name = name, Person = new Person { Name = person.name }}
                }
            }
        } 
    }
}

Answer 1

我对我的答案做了一些假设： 1. 我们只插入新电影，而不更新数据库中已有的电影。2. 我们使用实体框架来进行插入。3. 正在添加的电影中的人物尚未在与其他电影关联的数据库中。4. 每部电影都有演员阵容，每个演员至少有一个角色。

冒着被赶下酷孩子巴士的风险，我的解决方案不使用 LINQ，尽管我确信可以修改它来这样做。请注意，使用 EF，您无需设置关联的两端即可将其插入数据库。

// Lookup is necessary because a person might be in more than one movie.
var personLookup = new Dictionary<string,Person>();

foreach (var contractMovie in dataContractMovies)
{
    var movie = new Movie() { Title = contractMovie.Title };

    foreach (var contractPerson in contractMovie.Cast)
    {
        if (!personLookup.ContainsKey(contractPerson.Name))
        {
            personLookup.Add(contractPerson.Name, new Person() { Name = contractPerson.Name });
        }
        var person = personLookup[contractPerson.Name];

        foreach (var contractCharacter in contractPerson.Characters)
        {
            var character = new Character() { Name = contractCharacter.Name, Person = person, Movie = movie };

            dataContext.Characters.Add(character);
        }
    }
 }
 dataContext.SaveChanges();

如果数据契约将电影映射到角色而不是人（就像您在评论中建议的那样），您可以得到类似这样的结果：

var personLookup = new Dictionary<string, Person>();
var movie = dataContractMovies.Select(m => new Movie {
    Title = m.Title,
    Characters = m.Characters.Select(c => new Character() { Name = c.Name, Person = LookupPerson(c.Person, personLookup) }).ToList()
});

public Person LookupPerson(string personName, Dictionary<string, Person> personLookup)
{
        if (!personLookup.ContainsKey(personName))
        {
            personLookup.Add(personName, new Person() { Name = personName });
        }
        return personLookup[personName];
}