[英]ManualResetEvent throws NullReferenceException: Object reference not set to an instance of an object
[英]ViewBag throws NullReferenceException (Object Not Sent to Instance)
ViewBag Data拋出此異常,我不確定為什么嗎? 包含ViewBag.Data的行上的View類中的異常錯誤。 任何幫助將不勝感激!
<table>
<tr>
<th>Response Text</th>
<th>Date & Time of Update</th>
<th>Username</th>
</tr>
@foreach (OfficiumWebApp.Models.ResponseViewModel item in ViewBag.Data)
{
<tr>
<td>@item.ResponseText</td>
<td>
<td>@item.DateTimeOfUpdate</td>
<td>
<td>@item.Username</td>
<td>
</tr>
}
這是我的控制器中的方法:
[Authorize(Roles = "Customer")]
public ActionResult Index()
{
var yyy = (from a in db.Responses select new ResponseViewModel {ResponseText = a.ResponseText, DateTimeOfUpdate = a.DateTimeOfUpdate.ToString(), Username = a.UserName});
ViewBag.Data = yyy;
var LogResponses = from b in db.Responses where b.LogID == LogID select b;
return View(LogResponses.ToList());
}
您需要在視圖中為ViewBag.Data
添加一個null
值檢查,如下所示:
@if (ViewBag.Data != null)
{
foreach (OfficiumWebApp.Models.ResponseViewModel item in ViewBag.Data)
{
<tr>
<td>@item.ResponseText</td>
<td>
<td>@item.DateTimeOfUpdate</td>
<td>
<td>@item.Username</td>
<td>
</tr>
}
}
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