编辑列表<String> MVC 4

Question

我正在尝试创建一个页面来编辑'Person'，但是我遇到了如何编辑List对象的问题（通过编辑，我的意思是如何动态地添加一个电子邮件到名单）。研究在线以及在stackoverflow已导致我编辑模板，然后动态添加项目与Ajax。但是，我错过了某处的连接。要么为新电子邮件创建未绑定的空文本框，要么获取空引用错误。

型号：

[DynamoDBTable("people")] 
public class Person 
{ 
    [DynamoDBHashKey] 
    [DynamoDBProperty(AttributeName = "name")] 
    public string Name{ get; set; } 

    [DynamoDBRangeKey] 
    [DynamoDBProperty(AttributeName = "id")] 
    public string ID { get; set; } 

    [DynamoDBProperty(AttributeName = "emails")] 
    public List<string> Emails{ get; set; } 

    public Person() 
    { 

    } 
} 

查看：

<div id="emails" class="row"> 
    <div class="form-group col-xs-6 col-sm-6"> 
     @Html.LabelFor(x => x.Emails) 
     @Html.EditorFor(x => Model.Emails, new { @class = "form-control"}) 
    </div> 
    <button id="addEmail">Add</button> 
</div> 

<script type="text/javascript"> 
     $("#addEmail").on('click', function (event) { 
      event.preventDefault(); 
      $.ajax({ 
       async: false, 
       url: '/controller/newEmail' 
      }).success(function (partialView) { 
       $('#emails').append(partialView); 
      }); 
     }); 
</script> 

EditorTemplate - 人：

@model Models.Person 

@for (int i = 0; i < Model.Emails.Count(); i++) 
{ 
    @Html.EditorFor(x => Model.Emails) 

} 

EditorTemplate - 字符串：

@model string 

@Html.TextBoxFor(model => Model) 

控制器：

public ActionResult newEmail() 
{ 
    var emails = new Person().Emails; 

    return PartialView("~/Views/Shared/EditorTemplates/string.cshtml", emails); 
} 

Answer 1

你Person.Emails对象为空并且尚未初始化

public ActionResult newEmail() 
{ 
    var emails = new Person().Emails; 

    return PartialView("~/Views/Shared/EditorTemplates/string.cshtml", emails); 
} 

将其更改为：

public ActionResult newEmail() 
{ 
    var emails = new Person().Emails = new List<string>(); 

    return PartialView("~/Views/Shared/EditorTemplates/string.cshtml", emails); 
}