在ASP.NET MVC中发布后,Model.List为null

Question

我知道还有其他问题,但我想要更好的解释.

我想用我的Model.List显示一个表,在POST之后我仍然需要访问该列表.今天没有发生这种情况.

这是我的cshtml:

@foreach (var student in Model.ListSchedulingDetails)
    {
        <tr>
            <td width="150">
                @Html.DisplayFor(modelItem => student.SchedulingDate)
            </td>
            <td width="250">
                @Html.DisplayFor(modelItem => student.TeacherName)
            </td>
            <td width="250">
                @Html.DisplayFor(modelItem => student.StudentName)
            </td>
            <td width="150">
                @Html.DisplayFor(modelItem => student.SchedulingHour)
            </td>
            <td width="250">
                @Html.DisplayFor(modelItem => student.SchedulingObservation)
            </td>
        </tr>
    }

POST后,我的Model.ListSchedulingDetails为null.发生了什么？

Answer 1

这里有两件事:

1. DisplayFor()仅用于展示.对于发布,我们需要输入元素,如HiddenFor(),TextBoxFor()

2. 您需要将它们编入索引以便在收集时回发,这样做foreach无济于事

你的代码需要像:

 @for (int i=0; i< Model.ListSchedulingDetails.Count; i++)
 {
     <tr>
        <td width="150">
            @Html.DisplayFor(modelItem => ListSchedulingDetails[i].SchedulingDate)
            @Html.HiddenFor(modelItem => ListSchedulingDetails[i].SchedulingDate)
        </td>
        <td width="250">
            @Html.DisplayFor(modelItem => ListSchedulingDetails[i].TeacherName)
            @Html.HiddenFor(modelItem => ListSchedulingDetails[i].SchedulingDate)
        </td>
        <td width="250">
            @Html.DisplayFor(modelItem => ListSchedulingDetails[i].StudentName)
           @Html.HiddenFor(modelItem => ListSchedulingDetails[i].SchedulingDate)
        </td>
        <td width="150">
           @Html.DisplayFor(modelItem => ListSchedulingDetails[i].SchedulingHour)
           @Html.HiddenFor(modelItem => ListSchedulingDetails[i].SchedulingDate)
        </td>
        <td width="250">
            @Html.DisplayFor(modelItem => ListSchedulingDetails[i].SchedulingObservation)
            @Html.HiddenFor(modelItem => ListSchedulingDetails[i].SchedulingDate)
        </td>
    </tr>
 }