如何使用LINQ为包含多行LIST的条目选择？

Question

I have a List of IJapaneseDictionaryEntry objects:

public interface IJapaneseDictionaryEntry
{
    int Sequence { get; }
    IEnumerable<IKanji> Kanjis { get; }
    IEnumerable<IReading> Readings { get; }
    IEnumerable<ISense> Senses { get; }
}

public interface IKanji
{
    string Text { get; }
    IEnumerable<KanjiInformation> Informations { get; }
    IEnumerable<Priority> Priorities { get; }
}

Which I am do a LINQ query on like this:

var a = entries.SelectMany(x => x.Kanjis)
               .Select(x => new { x.Text, x.Priorities });

Is there a way that I can filter this so I only retrieve entries that have at least one priority?

Answer 1

You can use Eumerable.Where :

var a = entries.SelectMany(x => x.Kanjis)
               .Where(x => x.Priorities.Any())
               .Select(x => new { x.Text, x.Priorities });

Or in query syntax:

var e =
    from entry in entries
    from kanji in entry.Kanjis
    where kanji.Priorities.Any()
    select new { kanji.Text, kanji.Priorities };