如果不需要所有属性，是否可以将数据从一个对象放到另一个对象？

Question

I have a list of PhraseAndScore

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; }
}

I'd like to use this data to populate a list of Phrase:

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; }
}

When I try this it gives me an error:

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

Is there a way I can take the PhraseAndScore data and fit the columns into Phrase or would I need to do a LINQ select and itemize every column?

I tried this also but it does not work:

     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

One possibility is to complete the select statement and initialize new Phrase out PhraseAndScore .

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

Another (more advanced) method would be to create an interface for your phrase and implement it by any object that is actually a phrase. Then, instead of a List<Phrase> you utilize a 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; }
}

Your PhraseAndScore class implements it:

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; }
}

Your Phrase class implements it the interface too:

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; }
}

Then instantiate the list:

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

EDIT

Oh, my bad. List<T> requires the T argument to be invariantly valid. You need a set that allows for covariant T . So you need to use 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>

Or, inside a method just use implicit typing:

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

Answer 2

Without reflection or automapper, no, there is not.

Consider designing your domain model better, eg using composition:

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

Did you try Automapper ? It is useful to convert and load similar objects to each other.