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Question

我有一个PhraseAndScore列表

public class PhraseAndScore
{
    public string PhraseId { get; set; }
    public int CategoryId { get; set; }
    public string English { get; set; }
    public string Romaji { get; set; }
    public string Kana { get; set; }
    public string Kanji { get; set; }
    public int Modified { get; set; }
    public bool Favorite { get; set; }
    public string WordType { get; set; }
    public bool Hidden { get; set; }
    public int OneHash { get; set; }
    public int TwoHash { get; set; }
    public int? FrequencyA { get; set; }
    public int? FrequencyB { get; set; }
    public int? FrequencyC { get; set; }
    public int? JapaneseForBusyPeople { get; set; }
    public int? AJlpt { get; set; }
    public int? TJlpt { get; set; }
    public bool Selected { get; set; }
    public int EnglishCorrect { get; set; }
    public int KanaCorrect { get; set; }
    public int RomajiCorrect { get; set; }
    public int KanjiCorrect { get; set; }
}

我想用这些数据填充一个词组列表：

public class Phrase
{
    public string PhraseId { get; set; }
    public int CategoryId { get; set; }
    public string English { get; set; }
    public string Romaji { get; set; }
    public string Kana { get; set; }
    public string Kanji { get; set; }
    public int Modified { get; set; }
    public bool Favorite { get; set; }
    public string WordType { get; set; }
    public bool Hidden { get; set; }
    public int OneHash { get; set; }
    public int TwoHash { get; set; }
    public int? FrequencyA { get; set; }
    public int? FrequencyB { get; set; }
    public int? FrequencyC { get; set; }
    public int? JapaneseForBusyPeople { get; set; }
    public int? AJlpt { get; set; }
    public int? TJlpt { get; set; }
    public bool Selected { get; set; }
}

当我尝试这个时，它给了我一个错误：

List<Phrase> all = db2.Query<PhraseAndScore>(select + filter);

有没有办法可以获取PhraseAndScore数据并使列适合Phrase，还是我需要进行LINQ选择并列出每列？

我也试过了，但它不起作用：

     List<Phrase> xx = all.Select(pas => new Phrase()
            {
                PhraseId = pas.PhraseId,
                CategoryId = pas.CategoryId,
                English = pas.English,
                Romaji = pas.Romaji,
                Kana = pas.Kana,
                Kanji = pas.Kanji,
                Modified = pas.Modified,
                Favorite = pas.Favorite,
                WordType = pas.WordType,
                Hidden = pas.Hidden,
                OneHash = pas.OneHash,
                TwoHash = pas.TwoHash,
                FrequencyA = pas.FrequencyA,
                FrequencyB = pas.FrequencyB,
                FrequencyC = pas.FrequencyC,
                JapaneseForBusyPeople = pas.JapaneseForBusyPeople,
                AJlpt = pas.AJlpt,
                TJlpt = pas.TJlpt,
                Selected = pas.Selected
            });

Answer 1

一种可能性是完成select语句并初始化新Phrase PhraseAndScore。

List<Phrase> all = db2.Query<PhraseAndScore>().Where(filter)
    .Select(pas => new Phrase 
        { 
            PhraseId = pas.PhraseId,
            CategoryId = pas.CategoryId
            .
            .
            .
        })

另一种（更高级的）方法是为您的短语创建一个接口，并通过任何实际上是短语的对象来实现它。然后，您使用List<Phrase> ...

而不是List<IPhrase>

public interface IPhrase
{
    string PhraseId { get; set; }
    int CategoryId { get; set; }
    string English { get; set; }
    string Romaji { get; set; }
    string Kana { get; set; }
    string Kanji { get; set; }
    int Modified { get; set; }
    bool Favorite { get; set; }
    string WordType { get; set; }
    bool Hidden { get; set; }
    int OneHash { get; set; }
    int TwoHash { get; set; }
    int? FrequencyA { get; set; }
    int? FrequencyB { get; set; }
    int? FrequencyC { get; set; }
    int? JapaneseForBusyPeople { get; set; }
    int? AJlpt { get; set; }
    int? TJlpt { get; set; }
    bool Selected { get; set; }
}

您的PhraseAndScore类实现了它：

public class PhraseAndScore : IPhrase
{
    public string PhraseId { get; set; }
    public int CategoryId { get; set; }
    public string English { get; set; }
    public string Romaji { get; set; }
    public string Kana { get; set; }
    public string Kanji { get; set; }
    public int Modified { get; set; }
    public bool Favorite { get; set; }
    public string WordType { get; set; }
    public bool Hidden { get; set; }
    public int OneHash { get; set; }
    public int TwoHash { get; set; }
    public int? FrequencyA { get; set; }
    public int? FrequencyB { get; set; }
    public int? FrequencyC { get; set; }
    public int? JapaneseForBusyPeople { get; set; }
    public int? AJlpt { get; set; }
    public int? TJlpt { get; set; }
    public bool Selected { get; set; }
    public int EnglishCorrect { get; set; }
    public int KanaCorrect { get; set; }
    public int RomajiCorrect { get; set; }
    public int KanjiCorrect { get; set; }
}

您的Phrase类也实现了界面：

public class Phrase : IPhrase
{
    public string PhraseId { get; set; }
    public int CategoryId { get; set; }
    public string English { get; set; }
    public string Romaji { get; set; }
    public string Kana { get; set; }
    public string Kanji { get; set; }
    public int Modified { get; set; }
    public bool Favorite { get; set; }
    public string WordType { get; set; }
    public bool Hidden { get; set; }
    public int OneHash { get; set; }
    public int TwoHash { get; set; }
    public int? FrequencyA { get; set; }
    public int? FrequencyB { get; set; }
    public int? FrequencyC { get; set; }
    public int? JapaneseForBusyPeople { get; set; }
    public int? AJlpt { get; set; }
    public int? TJlpt { get; set; }
    public bool Selected { get; set; }
}

然后实例化列表：

List<IPhrase> all = db2.Query<PhraseAndScore>().Where(filter).ToList();

修改

哦，我的坏。 List<T>要求T参数不变地有效。您需要一个允许协变T的集合。所以你需要使用IEnumerable<out T>。 More info on covariance.

IEnumerable<IPhrase> all = db2.Query<PhraseAndScore>().Where(filter).ToList(); // or ToArray() or whatever implementation of IEnumerable<out IPhrase>

或者，在方法内部只使用隐式输入：

var all = db2.Query<PhraseAndScore>().Where(filter).ToList(); // or ToArray() or whatever implementation of IEnumerable<out IPhrase>

Answer 2

没有反射或自动播放器，不，没有。

考虑更好地设计您的域模型，例如使用构图：

public class Phrase
{
    public string PhraseId { get; set; }
    public int CategoryId { get; set; }
    public string English { get; set; }
    public string Romaji { get; set; }
    public string Kana { get; set; }
    public string Kanji { get; set; }
    public int Modified { get; set; }
    public bool Favorite { get; set; }
    public string WordType { get; set; }
    public bool Hidden { get; set; }
    public int OneHash { get; set; }
    public int TwoHash { get; set; }
    public int? FrequencyA { get; set; }
    public int? FrequencyB { get; set; }
    public int? FrequencyC { get; set; }
    public int? JapaneseForBusyPeople { get; set; }
    public int? AJlpt { get; set; }
    public int? TJlpt { get; set; }
    public bool Selected { get; set; }
}

public class Score
{
    public int EnglishCorrect { get; set; }
    public int KanaCorrect { get; set; }
    public int RomajiCorrect { get; set; }
    public int KanjiCorrect { get; set; }
}

public class ScoredPhrase
{
    public Phrase Phrase { get; set; }
    public Score Score { get; set; }
}

Answer 3

你试过Automapper吗？将类似的对象相互转换和加载很有用。

如果我不需要所有属性，我可以将数据从一个对象放到另一个对象吗？

3 个答案:

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