MVC3根据另一个编辑数据条目

Question

在我的应用程序中我想将类从第一个更改为第二个，例如取决于成绩的数据条目。

        <div class="editor-label">
        @Html.LabelFor(model => model.Class)
    </div>
    <div class="editor-field">
@Html.DropDownListFor(model => model.Class, new SelectList(new[] { "1st grade", "2nd grade", "3rd grade" }))
        @Html.ValidationMessageFor(model => model.Class)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.grade)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.grade)
        @Html.ValidationMessageFor(model => model.grade)
    </div>