EF4 CTP5多态查询

Question

我有一个类似如下的模型：

public class Employee
{
    public Employee()
    {
        TimeCards = new List<TimeCard>();
    }
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime HireDate { get; set; }
    public virtual ICollection<TimeCard> TimeCards { get; set; }
}
public class Manager : Employee
{
    public bool HasCompanyCar { get; set; }
}
public class Developer : Employee
{
    public string MainProgrammingLanguage { get; set; }
}

(如果this infrastructure很重要，我会使用它)。

我需要的是让所有不是经理的员工。只有一种OfType扩展方法。我需要的是NotOfType。

    var employees = unitOfWork.Employees
                   .FindAll()
                   .NotOfType<Manager>(); //or something similar
    var cards = unitOfWork.TimeCards.FindAll();

    var query = from e in employees
                from tc in cards
                where tc.Employee.Id == e.Id && e.Name.StartsWith("C")
                select tc;

离题:对于这种情况，继承是正确的选择吗？如何对其进行建模？我只是觉得继承把我引向了错误的道路。

Answer 1

也许您会发现NotOfType扩展方法应该更好，但这对您来说应该是有效的。

var employees = unitOfWork.Employees
               .Where(e => !(e is Manager));

var cards = unitOfWork.TimeCards.FindAll();

var query = from e in employees
            from tc in cards
            where 
               tc.Employee.Id == e.Id && 
               e.Name.StartsWith("C")                   
            select tc;

或者像这样：

var employees = unitOfWork.Employees
               .FindAll();

var cards = unitOfWork.TimeCards.FindAll();

var query = from e in employees
            from tc in cards
            where 
               tc.Employee.Id == e.Id && 
               !(e is Manager) &&
               e.Name.StartsWith("C")                   
            select tc;