如何动态添加或删除下拉列表？

Question

我试图在表单内部动态创建下拉列表，并将所有下拉列表和其他表单控件的选定值返回给控制器。

下拉列表的最小数目为1，并且可以存在的最大下拉列表数目为下拉列表中的选项数目。例如，如果选项数量为5，则下拉列表的数量范围可以从1到5。

下拉列表选项

public enum Subject: byte
{
   English = 0,
   Mathematics,
   Biology,
   Physics,
   Chemistry,
   Geography,
   History
}

模型

public class Student
{
   public int Id { get; set; }

   [Display(Name = "Name")]
   public string Name { get; set; }

   [Display(Name = "D.O.B")]
   public string DOB { get; set; }

    public string SelectedSubject { get; set; }

   //I want to create dynamic drop down lists for subjects
   //TODO: add supporting properties to get selected subjects
}

查看

...
@using (Html.BeginForm())
{
    <div class="form-horizontal">
        @Html.HiddenFor(model => model.Id)
        <div class="form-group>
            @Html.LabelFor(model => model.Name)
            <div class="col-md-10">
                @Html.EditorFor(model => model.Name)
            </div>
        </div>
        <div class="form-group>
            @Html.LabelFor(model => model.DOB)
            <div class="col-md-10">
                @Html.EditorFor(model => model.DOB)
            </div>
        </div>
        <div class="form-group>
            @Html.LabelFor(model => model.DOB)
            <div class="col-md-10">
                @Html.DropDownListFor(model => model.SelectedSubject, new SelectList(Enum.GetValues(typeof(Subject))))
            </div>
        </div>
        @*Add "Add subject" button"*@
        @*Add dropdown list, Add "Remove" button and shift Add button to the back*@
        @*the newly added dropdown list is just beside the previous one*@
        @*Number of dropdown list: 1 to 7*@
        @*If number of dropdown list is 7, add button is hidden*@
        @*If number of dropdown list is 1, delete button is hidden*@
        <div class="form-group">
            <div class="col-md-offset-2 col-md-10">
                <input type="submit" value=Create />
            </div>
        </div>
    </div>
}

控制器

//TODO: add more parameters to support getting the data from the dropdownlist
[HttpPost]
public ActionResult Create(Student student, **add other parameter to support dropdown list selected value**)
{
    ...
}

所有评论的地方都是我不确定要添加的区域。 预先感谢。