如何將信息添加到班級的列表中？

如果我有兩個類，像這樣：如何將信息添加到班級的列表中？

public class Department 
{ 
    public int Id { get; set; } 
    public string Name { get; set; } 
    public List<Employee> employees { get; set; } 
} 

public class Employee 
{ 
    public string Name { get; set; } 
    public string Job { get; set; } 
    public string Date { get; set; } 
}

然後，如果我這樣做：

var departments = new List<Department>(); 
Department d = new Department 
{ 
    Id = 1, 
    Name = "Depart1", 
}; 

Department d2 = new Department 
{ 
    Id = 2, 
    Name = "Depart2", 
}; 

departments.Add(d); 
departments.Add(d2);

我如何才能增加員工名單系類foreach循環？當我這樣做：

foreach(Department dmt in departments) 
{ 
    Employee worker = new Employee 
    { 
     Name = "Steve", 
     Job = "Cleanup", 
     Date = "Today", 
    }; 

    dmt.employees.Add(worker); 
}

我沒有得到任何生成錯誤，但沒有添加任何東西。有什麼建議麼？

來源

2012-03-11 Jack Null

當是'.employees'列表爲任何部門集到一個非空值？ – 2012-03-11 19:26:29

我很驚訝你沒有得到employees.Add（）的空引用異常。 – 2012-03-11 19:29:10

您沒有實例化employees屬性。您的類定義改成這樣：

public class Department 
{ 
    public int Id { get; set; } 
    public string Name { get; set; } 
    public List<Employee> employees { get; set; } 

    public Department() 
    { 
     employees = new List<Employee>(); 
    } 
}

或者，如果你不想使用構造函數來實例化employees財產，你只需要確保你這樣做，你嘗試添加一個Employee對象之前到List<Employee>。

來源

2012-03-11 19:26:32

您需要初始化您的Department類中的公共財產僱員
在此場景中，您可以在Department實例的構造函數中執行此操作。

public class Department 
{ 
    public int Id { get; set; } 
    public string Name { get; set; } 
    public List<Employee> employees { get; set; } 
    public Department() 
    { 
     employees = new List<Employee>(); 
    } 
}

來源

2012-03-11 19:27:42 Steve

嘗試這樣

public class Department 
{ 
    public int Id { get; set; } 
    public string Name { get; set; } 
    public List<Employee> employees { get; set; } 
    public Department() 
    { 
     employees = new List<Employee>(); 
    } 
} 

foreach(Department dmt in departments) 
{ 
    dmt.employees.Add(new Employee() { 

     // InterestedID = ((int)dataReader["JobId"]), 
     Name = "Steve", 
     Job = "Cleanup", 
     Date = "Today", 
    }); 
}

來源

2012-03-11 19:28:13 IamStalker

我會設計我的課像這樣，使員工列表只讀：

public class Department 
{ 
    private readonly List<Employee> _employees = new List<Employee>(); 

    public int Id { get; set; }  
    public string Name { get; set; }  
    public List<Employee> employees { get { return this._employees; }}  
}

來源

2012-03-11 19:32:40

如何將信息添加到班級的列表中？

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