在ASP.NET MVC4中,HtmlHelper为我们提供了Html.RadioButton()方法用来显示Radio Button单选按钮。如果想显示一组单选按钮,通常的做法是遍历一个集合把每个单选按钮显示出来。本篇尝试写一个扩展方法用来展示一组带验证的单选按钮。
首先来扩展HtmlHelper,扩展方法中接收一个SelectListItem的集合,遍历这个集合把每个单选按钮显示出来,并且让这些单选按钮具有不同的id属性值。
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Text;
using System.Web.Mvc.Html;
namespace System.Web.Mvc
{public static class HtmlExtensions{public static MvcHtmlString RadioButtonListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper,Expression<Func<TModel, TProperty>> expression, IEnumerable<SelectListItem> list){//获取元数据
var metaData = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);var sb = new StringBuilder();
if (list != null){foreach (var item in list){//把属性名和集合元素的Value值拼接作为元素的id
var id = string.Format("{0}_{1}", metaData.PropertyName, item.Value);//创建单选按钮
var label = htmlHelper.Label(id, HttpUtility.HtmlEncode(item.Text));var radio = htmlHelper.RadioButtonFor(expression, item.Value, new {id = id}).ToHtmlString();
sb.AppendFormat("<div class=\"RadioButton\">{0}{1}</div>", radio, label);
}}return MvcHtmlString.Create(sb.ToString());
}}}
假设,现在有一个View Model,其中的一个属性要求必须。
using System.ComponentModel.DataAnnotations;
namespace MvcApplication1.Models
{public class Vm{[Required(ErrorMessage = "必填")]
public int CityId { get; set; }}}
以下City类的集合将作为所有Radio Button的数据源。
namespace MvcApplication1.Models
{public class City{public int Id { get; set; }public string Name { get; set; }}}
在HomeController中,提供一个Action方法啊,把City的集合转换成SelectListItem集合传递给视图。
using System.Collections.Generic;
using System.Linq;
using System.Web.Mvc;
using MvcApplication1.Models;
namespace MvcApplication1.Controllers
{public class HomeController : Controller{public ActionResult Index()
{List<City> cities = new List<City>()
{new City(){Id = 1, Name = "青岛"},new City(){Id = 2, Name = "济南"},new City(){Id = 3, Name = "平度"}};ViewData["c"] = from c in citiesselect new SelectListItem() {Text = c.Name, Value = c.Id.ToString()};
return View(new Vm());}[HttpPost]public ActionResult Index(Vm vm)
{if (ModelState.IsValid)
{return Content(vm.CityId.ToString());
}else
{return View(vm);
}}}}
在_Layout.csthml中,必须具备客户端验证js。
<head><meta charset="utf-8" />
<meta name="viewport" content="width=device-width" /><title>@ViewBag.Title</title>@Styles.Render("~/Content/css")
@Scripts.Render("~/bundles/jquery")
@Scripts.Render("~/bundles/jqueryval")
</head><body>@RenderBody()@RenderSection("scripts", required: false)</body>
在Home/Index.chtml中,使用扩展方法显示Radio Button组。
@model MvcApplication1.Models.Vm@{ViewBag.Title = "Index";
Layout = "~/Views/Shared/_Layout.cshtml";
}<style type="text/css">
.RadioButton { float:left; }
</style>@using (Html.BeginForm("Index", "Home", FormMethod.Post, new {id = "addForm"})){@Html.RadioButtonListFor(v => v.CityId, ViewData["c"] as IEnumerable<SelectListItem>)@Html.ValidationMessageFor(v => v.CityId)<br/><br/><input type="submit" value="提交"/>}