Question

我遇到了我的对象实例的问题，它给了我一个我不理解的错误

List<Event> events = parseResponse.Deserialize<List<Event>>(_responseAsString);
ViewBag.eventss = events;

HTML

<table id="eventist" border="0" cellspacing="0" cellpadding="0">
<thead>
    <tr>
        <th>
            event_key
        </th>
         <th>
            user_token
        </th>                
        <th>
            event_set_key
        </th>           
        <th>
            event_type
        </th>
         <th>
          event_date
        </th>
          <th>
            event_amount
        </th>
         <th>
            event_location_key
        </th>                
        <th>
            event_location_name
        </th>           
        <th>
            event_location_city
        </th>
         <th>
          event_location_state
        </th>
        <th>
            event_location_country
        </th>
         <th>
          event_acknowledged
        </th>
    </tr>
</thead>
<tbody>
<%List<StopMalaria.Models.Event> events= ViewBag.eventss;%>
<% foreach (var item in events)
   { %>

    <tr>
        <td>
            <%: item.event_key%>
        </td>
        <td>
              <%: item.user_token%>
        </td>               
        <td>
            <%: item.event_set_key%>
        </td>           
        <td>
            <%: item.event_type%>
        </td> 
         <td>
            <%: item.event_date%>
        </td>
        <td>
              <%: item.event_amount%>
        </td>               
        <td>
            <%: item.event_location_key%>
        </td>           
        <td>
            <%: item.event_location_name%>
        </td> 
         <td>
            <%: item.event_location_city%>
        </td>
        <td>
              <%: item.event_location_state%>
        </td>               
        <td>
            <%: item.event_location_country%>
        </td>           
        <td>
            <%: item.event_acknowledged%>
        </td>                   
    </tr>

<% } %>
</tbody>
</table>

所以我这样做了。现在它说[NullReferenceException：对象引用未设置为对象的实例。]并且我的<% foreach(var item in events)突出显示为红色。

我已经有一个包含所有元素的类

   public class Event
   {
     public string event_key { get; set; }
     public string user_token { get; set; }
     public string event_set_key { get; set; }
    public string event_type { get; set; }
    public string event_date { get; set; }
    public string event_amount { get; set; }
    public string event_location_key { get; set; }
    public string event_location_name { get; set; }
    public string event_location_city { get; set; }
    public string event_location_state { get; set; }
    public string event_location_country { get; set; }
    public string event_acknowledged { get; set; }
 }

Answer 1

为您的视图添加一个viewmodel，示例可能看起来像。在您的操作中也使用此viewmodel：

 public class EventListModel
    {
        public EventListModel()
        {
            EventList = new List<Event>();
        }

        public string FormId { get; set; }
        public string ProgramId { get; set; }
        public string FormName { get; set; }

        public IList<Event> EventList { get; set; }
    }

NullReferenceException：未将对象引用设置为对象的实例。在foreach循环中

1 个答案: