asp.net-mvc - 在 ASP.NEt MVC 3 中的 Html.BeginForm() 中传递 DropDownList 的 SelectedValue

Question

这是我的查看代码：

@using(Html.BeginForm(new { SelectedId = /*SelectedValue of DropDown*/ })) {

 <fieldset>

     <dl>
       <dt>
           @Html.Label(Model.Category)
       </dt>
       <dd>
        @Html.DropDownListFor(model => Model.Category, CategoryList)
       </dd>
    </dl>

 </fieldset>
 <input type="submit" value="Search" />


}

如代码所示，我需要将dropdown选定的值传递给BeginForm()Html 帮助器中的操作。你的建议是什么？

Answer 1

提交表单时将传递所选值，因为下拉列表由<select>元素表示。您只需要调整您的视图模型，使其具有一个名为SelectedId例如您将绑定下拉列表的属性：

@using(Html.BeginForm() )
{
    <fieldset>
        <dl>
            <dt>
                @Html.LabelFor(x => x.SelectedId)
            </dt>
           <dd>
                @Html.DropDownListFor(x => x.SelectedId, Model.CategoryList)
           </dd>
        </dl>
    </fieldset>

    <input type="submit" value="Search" />
}

这假设以下视图模型：

public class MyViewModel
{
    [DisplayName("Select a category")]
    public int SelectedId { get; set; }

    public IEnumerable<SelectListItem> CategoryList { get; set; }
}

这将由您的控制器处理：

public ActionResult Index()
{
    var model = new MyViewModel();
    // TODO: this list probably comes from a repository or something
    model.CategoryList = new[]
    {
        new SelectListItem { Value = "1", Text = "category 1" },
        new SelectListItem { Value = "2", Text = "category 2" },
        new SelectListItem { Value = "3", Text = "category 3" },
    };
    return View(model);
}

[HttpPost]
public ActionResult Index(MyViewModel model)
{
    // here you will get the selected category id in model.SelectedId
    return Content("Thanks for selecting category id: " + model.SelectedId);
}