在调试中已经显示数据时，将数据附加到运行时将引发null异常

Question

将数据附加到表数据元素时，foreach文件中的cshtml引发空异常

我尝试调试

@foreach (onlineStore.Areas.Admin.Models.orderModel i in ViewBag.data)
{
       <tr>
           <td>@i.uName</td>
           <td>@i.oDate</td>
           <td>@i.tCost</td>  //throws exception here 
           <td>
           <a asp-action="Details" asp-controller="Admin" asp-area="Admin" asp-route-userid="@ViewBag.i.oID" class="btn btn-primary">Details</a>
           </td>
       </tr>
}

here is an image of the data at he debugging

例外是：

  

“ Microsoft.CSharp.RuntimeBinder.RuntimeBinderException：'无法   在空引用上执行运行时绑定'“

Answer 1

使用前，您需要检查ViewBag.data != null。

可能将错误的变量@ViewBag.i.oID更改为i.oID

@if (ViewBag.data != null)
{
     foreach (onlineStore.Areas.Admin.Models.orderModel i in ViewBag.data)
     {
         <tr>
             <td>@i.uName</td>
             <td>@i.oDate</td>
             <td>@i.tCost</td>  //throws exception here
             <td>
                 <a asp-action="Details" asp-controller="Admin" asp-area="Admin" asp-route-userid="@i.oID" class="btn btn-primary">Details</a>
             </td>
         </tr>
     }
}