c# - 如何使用 LINQ C# 筛选内部集合

Question

我需要使用 LINQ 过滤集合的内部集合以获取记录。

public class MobileModel : Notify
{
    private string _brand = string.Empty;
    private ObservableCollection<MobileModelInfo> _model = new ObservableCollection<MobileModelInfo>();
    private string _os = string.Empty;

    public string Brand
    {
        get { return _brand; }
        set { _brand = value; OnPropertyChanged(); }
    }
    public ObservableCollection<MobileModelInfo> Model
    {
        get { return _model; }
        set { _model = value; OnPropertyChanged(); }
    }

    public string OS
    {
        get { return _os; }
        set { _os = value; OnPropertyChanged(); }
    }
}

public class MobileModelInfo
{
    public string Name { get; set; }
    public string Catagory { get; set; }
    public string Year { get; set; }
}


public void GetMobile()
    {
        List<MobileModel> mList = new List<MobileModel>();
        List<MobileModelInfo> modList = new List<MobileModelInfo>();
        MobileModel mob = new MobileModel();

        modList.Clear();
        mob.Brand = "Apple";
        modList.Add(new MobileModelInfo { Name = "iPhone 4", Catagory = "Smart Phone", Year = "2011" });
        modList.Add(new MobileModelInfo { Name = "iPhone 5", Catagory = "Smart Phone", Year = "2013" });
        modList.Add(new MobileModelInfo { Name = "iPhone 6", Catagory = "Premium Smart Phone", Year = "2015" });
        mob.Model = new ObservableCollection<MobileModelInfo>(modList);
        mob.OS = "IOS";
        mList.Add(mob);

        mob = new MobileModel();
        modList.Clear();
        mob.Brand = "Samsung";
        modList.Add(new MobileModelInfo { Name = "S4", Catagory = "Smart Phone", Year = "2011" });
        modList.Add(new MobileModelInfo { Name = "S5", Catagory = "Smart Phone", Year = "2013" });
        modList.Add(new MobileModelInfo { Name = "S6", Catagory = "Ultra Smart Phone", Year = "2015" });
        mob.Model = new ObservableCollection<MobileModelInfo>(modList);
        mob.OS = "Android";
        mList.Add(mob);

        mob = new MobileModel();
        modList.Clear();
        mob.Brand = "MicroSoft";
        modList.Add(new MobileModelInfo { Name = "Lumina 9900", Catagory = "Phone", Year = "2011" });
        modList.Add(new MobileModelInfo { Name = "Opera X220", Catagory = "Smart Phone", Year = "2013" });
        mob.Model = new ObservableCollection<MobileModelInfo>(modList);
        mob.OS = "Windows";
        mList.Add(mob);

        mob = new MobileModel();
        modList.Clear();
        mob.Brand = "Sony Ericssion";
        modList.Add(new MobileModelInfo { Name = "S4", Catagory = "Smart Phone", Year = "2011" });
        modList.Add(new MobileModelInfo { Name = "S5", Catagory = "Smart Phone", Year = "2013" });
        modList.Add(new MobileModelInfo { Name = "S6", Catagory = "Ultra Smart Phone", Year = "2015" });
        mob.Model = new ObservableCollection<MobileModelInfo>(modList);
        mob.OS = "Android";
        mList.Add(mob);

        MobileList = new ObservableCollection<MobileModel>(mList);
    }

ObservableCollection MobileList 具有三个属性 Brand、Model 和 OS。模型属性又是一个 ObservableCollection，在 MobileModelInfo 类中具有三个属性名称、类别和年份。

我需要一个集合，它应该在内部集合 MobileModelInfo 中包含 Year 2011。其余记录不需要。

在三星中它应该只包含

mob.Brand = "Samsung";
modList.Add(new MobileModelInfo { Name = "S4", Catagory = "Smart Phone", Year = "2011" });
mob.OS = "Android";

实际的初始输出屏幕截图是

预期输出是

Answer 1

使用 SelectMany() :

MobileList.SelectMany(x => x.Model).Where(m=>m.Year==2011)