Question

我正在使用Entity Framework 5和MVC 4代码的第一种方法。我对这两个都很新，所以我可能做了一个简单的错误，我试图从数据库中删除多对多的关系。我可以添加关系很好，但当我想删除它时，我得到一个错误。

我必须与多对多的关系表。我有Employee类和演绎类：

通过ICollection链接到Deduction类的Employee类：

public class Employee
{

    public int EmployeeID { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }
    public int PhoneNumber { get; set; }
    public int CellNumber { get; set; }
    public string Address1 { get; set; }
    public string Address2 { get; set; }
    public string City { get; set; }
    public int PostalCode { get; set; }
    public string BankName { get; set; }
    public int BankAccountNumber { get; set; }
    public string PayInterval { get; set; }
    public double NormalRate { get; set; }
    public double OvertimeRate { get; set; }
    public double SetHours { get; set; }
    public DateTime DateOfEmployment { get; set; }
    public DateTime LastPaymentRecieved { get; set; }
    public string Active { get; set; }
    public int JobID { get; set; }

    public ICollection<Holiday> holiday { get; set; }
    public ICollection<Bonus> bonus { get; set; }
    public ICollection<Absent> absent { get; set; }
    public Job Job { get; set; }
    public ICollection<Deduction> Deductions { get; set; }
    public ICollection<HoursWorked> HoursWorke { get; set; }
    public ICollection<Payroll> Payrolls { get; set; }
}

通过ICollection链接到Employee类的扣除类：

public class Deduction
{

    public int DeductionID { get; set; }
    public string Name { get; set; }
    public string Type { get; set; }
    public double Amount { get; set; }

    public ICollection<Employee> Employee { get; set; }
    public ICollection<Payroll> Payroll { get; set; }
}

以下是我目前删除的代码：

    public void RemoveEmployeeDeduction(int empID, int dedID)
    {
        var employee = db.Employee.FirstOrDefault(x => x.EmployeeID == empID);

        var ded = db.Deduction.FirstOrDefault(x => x.DeductionID == dedID);

        employee.Deductions.Remove(ded);
        db.SaveChanges();

    }

我确实检查了员工和我要删除的扣除是否正确获取。我注意到在employee.Deductions.Remove（ded），扣减为空。这是错误：

Code

我也尝试了堆栈溢出的多个答案，但似乎没有工作，所以也许我的代码的一个例子可以帮助我。

提前致谢。

修改

我已通过添加以下内容解决了此错误：问题是我在检索员工时没有包含扣减。它现在按预期工作。

    public void RemoveEmployeeDeduction(int empID, int dedID)
    {
        var employee = db.Employee.Include("Deductions").FirstOrDefault(x => x.EmployeeID == empID);

        var ded = db.Deduction.FirstOrDefault(x => x.DeductionID == dedID);

        employee.Deductions.Remove(ded);
        db.SaveChanges();

    }

MVC 4 Entity Framework 5无法删除多对多关系

0 个答案: