Question

我想将List分配给成员变量（变量是List），但我总是收到错误消息：System.StackOverflowException未处理，我不知道原因，请参阅下面的代码：< / p>

public class Employee
{
    public int EmployeeID { get; set; }
    public string EmployeeName { get; set; }
    public int DeptID { get; set; }
}

public class Department
{
    public int DeptID { get; set; }
    public string DeptName { get; set; }
    public List<Employee> Employees
    {
        set { Employees = value; }
        //get { return EmployeeDataAccessLayer.getEmployeesByDeptID(DeptID); }
        get { return Employees; }
    }
}
public class EmployeeDataAccessLayer
{
    public static List<Employee> getEmployeesByDeptID(int deptID)
    {
        string conStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        string sqlStr = "select * from tblemployee where deptid = :deptid order by employeeid asc";
        List<Employee> employees = new List<Employee>();
        using (OracleConnection ocon = new OracleConnection(conStr))
        {
            OracleCommand ocmd = new OracleCommand(sqlStr, ocon);
            ocmd.Parameters.Add(":deptid", deptID);
            ocmd.Connection.Open();
            OracleDataReader rdr = ocmd.ExecuteReader();
            while (rdr.Read())
            {
                Employee employee = new Employee();
                employee.EmployeeID = Convert.ToInt32(rdr["EMPLOYEEID"]);
                employee.EmployeeName = rdr["NAME"].ToString();
                employee.DeptID = Convert.ToInt32(rdr["DEPTID"]);
                employees.Add(employee);
            }
        }
        return employees;
    }
}

public class DepartmentDataAccessLayer
{

    public static List<Department> getAllDepartments()
    {
        string conStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        string sqlStr = "select * from tbldepartment order by departmentid asc";
        List<Department> depts = new List<Department>();

        using (OracleConnection ocon = new OracleConnection(conStr))
        {
            OracleCommand ocmd = new OracleCommand(sqlStr, ocon);
            ocmd.Connection.Open();
            OracleDataReader rdr = ocmd.ExecuteReader();
            while (rdr.Read())
            {
                Department dept = new Department();
                dept.DeptID = Convert.ToInt32(rdr["DEPARTMENTID"]);
                dept.DeptName = rdr["NAME"].ToString();
                dept.Employees = EmployeeDataAccessLayer.getEmployeesByDeptID(dept.DeptID);
                depts.Add(dept);
            }
        }

        return depts;
    }
}

所以，我调试它，发现异常发生在：

set { Employees = value;}

见下面的截图：

我真的不知道为什么，你能告诉我原因还是给我一些建议？

Answer 1

在你的情况下，当你为Employees分配一些东西时，它的setter会再次触发它分配给同一个变量，所以同样的过程会继续进行，这会导致无限分配，这就是你得到那个异常的原因。克服这个改变这样的属性定义：

private List<Employee> _Employees
public List<Employee> Employees
{
    set { _Employees = value; }      
    get { return _Employees; }
}

或者像这样：

public List<Employee> Employees { get; set; }

Answer 2

如果您使用get和set在C＃中设置值，那么您需要做的只是

public List<Employee> Employees{get; set;}

使用空的get和set块，将自动分配该值。在你的代码中，你实际上一遍又一遍地调用你的变量的set函数，直到发生StackOverflow异常

有关属性here

的更多信息

Answer 3

因为您将Employees设置为value，将Employees设置为value，将Employees设置为value即设置public List<Employee> Employees { get; set; } .......等等，直到堆栈溢出。

因为您没有使用私有变量来保存员工，所以您可以使用auto-getter和-setter将值设置为自身，就像其他属性一样：

private List<Employee> _employees;
public List<Employee> Employees
{
    set { _employees = value; }
    get { return _employees; }
}

否则，设置一个私有变量来保存员工列表。这可以使用

{{1}}

为成员变量赋值失败，发生StackOverflowException

3 个答案: