将值分配到列表< object>在模型类中

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public class Parameter { public int Id {get;set;} public string name {get;set;} public List<Phonenumber> Phonenumbers{get;set} } public class Phonenumber { public string number1 {get;set;} public string number2 {get;set;} public string number3 {get;set;} }

public ActionResult SmeDirPage(Phonenumber number) { Parameter para = new Parameter (); // How do i assign value to para.Phonenumbers.number1 }

我尝试过： 请问如何将值传递到此列表

What I have tried: Please how can i pass values to this list

public ActionResult SmeDirPage(Phonenumber number) { Parameter para = new Parameter (); foreach(var item in para.Phonenumbers) // Error **Object reference not set to an instance of an object** { item.number1 = number.number1; item.number2 = number.number2; item.number3 = number.number3; } }

推荐答案

你已经将Phonenumbers定义为List但是没有你是在创建列表所以para.Phonenumbers总是为null。您可以在构造函数中创建一个新List。 You've define Phonenumbers to be a List but at no point are you creating the list so para.Phonenumbers is always going to be null. You can create a new List in the constructor. public class Parameter { public int Id {get;set;} public string name {get;set;} public List<Phonenumber> Phonenumbers{get;set} public Parameter() { this.Phonenumbers = new List<Phonenumber>(); } }

你的代码没有意义，因为你的 Phonenumbers 类型列表< Phonenumber> 的属性将始终为空值，因此它永远不会进入 foreach-loop 即使您初始化列表。 Your code doesn't make sense because your Phonenumbers property of type List<Phonenumber> will always have an empty value, thus it will never go inside your foreach-loop even if you initialize your List. Quote：

请问如何将值传递给此列表

Please how can i pass values to this list

您不需要循环为您的值分配值列表因为它已经预期某种类型 Phonenumber 。你需要做的就是这样：

You don't need a loop to assign values to your List because it's already expecting a type of Phonenumber. What you need to do is simply just like this:

var phoneNumbers = new List<Phonenumber>(); phoneNumbers.Add(numbers);

然后您可以将 phoneNumbers 值分配给您的参数这样的对象：

You can then assign the phoneNumbers value to your Parameter object like this:

Parameter para = new Parameter(); para.Id = 1; para.name = "Vynn Markus"; para.Phonenumbers = phoneNumbers;

完全放入它们，你的整个 ActionResult 方法现在看起来像这样：

To put them altogether, your whole ActionResult method would now look something like this:

public ActionResult SmeDirPage(Phonenumber numbers) { var phoneNumbers = new List<Phonenumber>(); phoneNumbers.Add(numbers); Parameter para = new Parameter(); para.Id = 1; para.name = "Vynn Markus"; para.Phonenumbers = phoneNumbers; }