具有嵌套类的Lambda

Question

我刚刚发布了这个问题但得到了我的问题的部分答案,所以我想我发布了更多解释,希望得到更准确的答案.我有2个班:

public class Employee
{
    public string Name { get; set; }
    public List<Cars> Cars { get; set; }
}

public class Car
{
    public int CarID { get; set; }
    public CarTypes CarType { get; set; }
    public enum CarTypes
    {
        Van,
        SmallCar
    }
}

我试图只获得所有已经分配了使用Lambda忽略那些使用SmallCars的员工的员工,我尝试了这一行:

List<Employee> EmployeesWithVans = AllEmployees.Where(emps => emps.Car.Any(cartype => cartype.CarType == Car.CarTypes.Van)).ToList();

但是,如果至少有一辆面包车被分配给一个员工(.Any),如果我尝试(.All)它会带回任何东西,因为并非所有员工都有范.

是否可以使用嵌套的Lambda实现这一点？

谢谢.

编辑:

Employee Mark = new Employee();
Mark.Cars.Add(new Car() { CarType = Car.CarTypes.Van, CarID = 12 });
Mark.Cars.Add(new Car() { CarType = Car.CarTypes.Van, CarID = 13 });
Mark.Cars.Add(new Car() { CarType = Car.CarTypes.SmallCar, CarID = 14 });

Employee Lisa = new Employee();
Lisa.Cars.Add(new Car() { CarType = Car.CarTypes.Van, CarID = 15 });
Lisa.Cars.Add(new Car() { CarType = Car.CarTypes.SmallCar, CarID = 16 });
Lisa.Cars.Add(new Car() { CarType = Car.CarTypes.SmallCar, CarID = 17 });

    List<Employee> EmployeesWithVans should contain:

    Employee FilteredMark contains:
    Mark.Cars.Add(new Car() { CarType = Car.CarTypes.Van, CarID = 12 });
    Mark.Cars.Add(new Car() { CarType = Car.CarTypes.Van, CarID = 13 });

    Employee FilteredLisa contains:
    Mark.Cars.Add(new Car() { CarType = Car.CarTypes.Van, CarID = 15 });

Answer 1

试试这个：

List<Employee> Temp = AllEmployees.Where(emps => emps.Cars.Any(cartype => cartype.CarType == Cars.CarTypes.Van)).ToList();

List<Employee> EmployeesWithVans = (from item in Temp
           select new Employee{ 
                                     Name = item.Name, 
                                     Cars = (item.Cars.Where( car => car.CarType == Cars.CarTypes.Van)).ToList()
                               }).ToList();

这是我尝试过的（在 LINQPAD 中）：

void Main()
{
    List<Employee> AllEmployees = new List<Employee>();

    List<Cars> lcars1 = new List<Cars>();
    Cars car1 = new Cars();
    car1.CarType = Cars.CarTypes.Van;
    lcars1.Add(car1);lcars1.Add(car1);

    Cars car2 = new Cars();
    car2.CarType = Cars.CarTypes.SmallCar;
    lcars1.Add(car2);

    List<Cars> lcars2 = new List<Cars>();
    lcars2.Add(car1);lcars2.Add(car2);lcars2.Add(car2);

    AllEmployees.Add(new Employee(){ Name="emp1", Cars = lcars1});
    AllEmployees.Add(new Employee(){ Name="emp2", Cars = lcars2});
    AllEmployees.Add(new Employee(){ Name="emp3", Cars = lcars1 });
    AllEmployees.Add(new Employee(){ Name="emp4", Cars = lcars2});

    List<Employee> Temp = AllEmployees.Where(emps => emps.Cars.Any(cartype => cartype.CarType == Cars.CarTypes.Van)).ToList();

    List<Employee> EmployeesWithVans = (from item in Temp
            select new Employee{ 
                                        Name = item.Name, 
                                        Cars = (item.Cars.Where( car => car.CarType == Cars.CarTypes.Van)).ToList()
                                }).ToList();

    EmployeesWithVans.Dump();
}

输出：