Question

我是Razor的新手，我不知道为什么我选择的值不起作用。

var listItems = (List<Categories>)ViewBag.Categories;

用于

@for (var i = 0; i < Model.TagActivities.Count; i++)
{
    <tr>
        @Html.HiddenFor(modelItem => Model.TagActivities[i].TAGActivityId, new { htmlAttributes = new { @class = "form-control" } })
        @Html.HiddenFor(modelItem => Model.TagActivities[i].CategoryId, new { htmlAttributes = new { @class = "form-control"
         <td>
            @Html.EditorFor(modelItem => Model.TagActivities[i].ActivityName, new { htmlAttributes = new { @class = "form-control" } })
        </td>
        <td>
            @Html.EditorFor(modelItem => Model.TagActivities[i].ActivityDescription, new { htmlAttributes = new { @class = "form-control" } })
        </td>
        <td>
            @Html.DropDownListFor(modelItem => Model.TagActivities[i].Category.CategoryName, new SelectList(listItems, "CategoryId", "CategoryName", Model.TagActivities[i].Category.CategoryName), new { @class = "form-control" })
        </td>
        <td>
            @Html.EditorFor(modelItem => Model.TagActivities[i].AlertMinutes, new { htmlAttributes = new { @class = "form-control" } })
        </td>
        <td>
            @Html.EditorFor(modelItem => Model.TagActivities[i].IsDefault)
        </td>
    </tr>
}

请帮助。谢谢。

Answer 1

它不起作用，因为您传递的选定值与listItems中的对象的类型不同。一旦可能的解决方案，就是将您传递给SelectList的构造函数的值更改为所选对象：

new SelectList(listItems, "CategoryId", "CategoryName", Model.TagActivities[i].Category)

listItems是Categories类型的对象列表。因此，作为选定对象，您应该传递此类型的对象。

@HTML Dropdownlist选中的值

1 个答案: