ASP.NET MVC使用Session会话保持表单状态

using System.ComponentModel.DataAnnotations;namespace MvcApplication1.Models{    public class Player    {        public int Id { get; set; }        [Required(ErrorMessage = "必填")]        [Display(Name = "球员名称")]        public string Name { get; set; }    }}

using System.Collections.Generic;using System.ComponentModel.DataAnnotations;namespace MvcApplication1.Models{    public class Club    {        public Club()        {            this.Players = new List<Player>();        }        public int Id { get; set; }        [Required(ErrorMessage = "必填")]        [Display(Name = "俱乐部名称")]        public string Name { get; set; }        public List<Player> Players { get; set; }    }}

@model MvcApplication1.Models.Club@{    ViewBag.Title = "Index";    Layout = "~/Views/Shared/_Layout.cshtml";}<h2>Index</h2>@using (Html.BeginForm("Index", "Home", FormMethod.Post, new {id = "myForm"})){    @Html.LabelFor(m => m.Name)    @Html.TextBoxFor(m => m.Name)    @Html.ValidationMessageFor(m => m.Name)    <br/><br/>        <ul id="players" style="list-style-type: none">        @if (Model.Players != null)        {            foreach (var item in Model.Players)            {                Html.RenderAction("NewPlayerRow", "Home", new { player = @item });            }                    }    </ul>    <a id="addPlayer" href="javascript:void(0)" rel="external nofollow"  rel="external nofollow" >添加球员</a>        <br/><br/>        <div>        <a href="javascript:void(0)" rel="external nofollow"  rel="external nofollow"   id="gotoOther">到别的地方转转</a> &nbsp;        <input type="submit" id="up" value="提交" />    </div>}@section scripts{    <script src="~/Scripts/dynamicvalidation.js"></script>    <script type="text/javascript">        $(function () {            //添加关于Player的新行            $('#addPlayer').on("click", function() {                createPlayerRow();            });            //到别的页            $('#gotoOther').on("click", function() {                if ($('#myForm').valid()) {                    $.ajax({                        cache: false,                        url: '@Url.Action("BeforeGoToMustSave", "Home")',                        type: 'POST',                        dataType: 'json',                        data: $('#myForm').serialize(),                        success: function (data) {                            if (data.msg) {                                window.location.href = '@Url.Action("RealGoTo", "Home")';                            }                        },                        error: function (xhr, status) {                            alert("添加失败，状态码：" + status);                        }                    });                }            });        });        //添加品牌行        function createPlayerRow() {            $.ajax({                cache: false,                url: '@Url.Action("NewPlayerRow", "Home")',                type: "GET",                data: {},                success: function (data) {                    $('#players').append(data);                    $.validator.unobtrusive.parseDynamicContent('#players li:last', "#myForm");                },                error: function (xhr, status) {                    alert("添加行失败，状态码：" + status);                }            });        }    </script>}

//对动态生成内容客户端验证(function ($) {    $.validator.unobtrusive.parseDynamicContent = function (selector, formSelector) {        $.validator.unobtrusive.parse(selector);        var form = $(formSelector);        var unobtrusiveValidation = form.data('unobtrusiveValidation');        var validator = form.validate();        $.each(unobtrusiveValidation.options.rules, function (elname, elrules) {            if (validator.settings.rules[elname] == undefined) {                var args = {};                $.extend(args, elrules);                args.messages = unobtrusiveValidation.options.messages[elname];                //edit:use quoted strings for the name selector                $("[name='" + elname + "']").rules("add", args);            } else {                $.each(elrules, function (rulename, data) {                    if (validator.settings.rules[elname][rulename] == undefined) {                        var args = {};                        args[rulename] = data;                        args.messages = unobtrusiveValidation.options.messages[elname][rulename];                        //edit:use quoted strings for the name selector                        $("[name='" + elname + "']").rules("add", args);                    }                });            }        });    };})(jQuery);

   public class HomeController : Controller    {        private const string sessionKey = "myFormKey";        public ActionResult Index()        {            Club club = null;            if (Session[sessionKey] != null)            {                club = (Club) Session[sessionKey];            }            else            {                club = new Club();            }            return View(club);        }        //提交表单        [HttpPost]        public ActionResult Index(Club club)        {            if (ModelState.IsValid)            {                StringBuilder sb = new StringBuilder();                sb.Append(club.Name);                if (club.Players != null && club.Players.Count > 0)                {                    foreach (var item in club.Players)                    {                        sb.AppendFormat("--{0}", item.Name);                    }                }                //删除Session                //Session.Abandon();                //Session.Clear();                Session.Remove(sessionKey);                return Content(sb.ToString());            }            else            {                return View(club);            }        }        //添加新行        public ActionResult NewPlayerRow(Player player)        {            return PartialView("_NewPlayer", player ?? new Player());        }        //跳转之前把表单保存到Session中        [HttpPost]        public ActionResult BeforeGoToMustSave(Club club)        {            Session[sessionKey] = club;            return Json(new { msg = true });        }        //保存完Club的Session后真正跳转到的页面        public ActionResult RealGoTo()        {            return View();        }    }

<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>

@using MvcApplication1.Extension@model MvcApplication1.Models.Player<li  class="newcarcolorli">     @using (Html.BeginCollectionItem("Players"))      {        @Html.HiddenFor(model => model.Id)         <div>             @Html.LabelFor(m => m.Name)             @Html.TextBoxFor(m => m.Name)             @Html.ValidationMessageFor(m => m.Name)         </div>       }</li>

using System;using System.Collections.Generic;using System.Web;using System.Web.Mvc;namespace MvcApplication1.Extension{    public static class CollectionEditingHtmlExtensions    {        //目标生成如下格式        //<input autocomplete="off" name="FavouriteMovies.Index" type="hidden" value="6d85a95b-1dee-4175-bfae-73fad6a3763b" />        //<label>Title</label>        //<input class="text-box single-line" name="FavouriteMovies[6d85a95b-1dee-4175-bfae-73fad6a3763b].Title" type="text" value="Movie 1" />        //<span class="field-validation-valid"></span>        public static IDisposable BeginCollectionItem<TModel>(this HtmlHelper<TModel> html, string collectionName)        {            //构建name="FavouriteMovies.Index"            string collectionIndexFieldName = string.Format("{0}.Index", collectionName);            //构建Guid字符串            string itemIndex = GetCollectionItemIndex(collectionIndexFieldName);            //构建带上集合属性+Guid字符串的前缀            string collectionItemName = string.Format("{0}[{1}]", collectionName, itemIndex);            TagBuilder indexField = new TagBuilder("input");            indexField.MergeAttributes(new Dictionary<string, string>()            {                {"name", string.Format("{0}.Index", collectionName)},                {"value", itemIndex},                {"type", "hidden"},                {"autocomplete", "off"}            });            html.ViewContext.Writer.WriteLine(indexField.ToString(TagRenderMode.SelfClosing));            return new CollectionItemNamePrefixScope(html.ViewData.TemplateInfo, collectionItemName);        }        private class CollectionItemNamePrefixScope : IDisposable        {            private readonly TemplateInfo _templateInfo;            private readonly string _previousPrfix;            //通过构造函数，先把TemplateInfo以及TemplateInfo.HtmlFieldPrefix赋值给私有字段变量，并把集合属性名称赋值给TemplateInfo.HtmlFieldPrefix            public CollectionItemNamePrefixScope(TemplateInfo templateInfo, string collectionItemName)            {                this._templateInfo = templateInfo;                this._previousPrfix = templateInfo.HtmlFieldPrefix;                templateInfo.HtmlFieldPrefix = collectionItemName;            }            public void Dispose()            {                _templateInfo.HtmlFieldPrefix = _previousPrfix;            }        }        /// <summary>        ///         /// </summary>        /// <param name="collectionIndexFieldName">比如，FavouriteMovies.Index</param>        /// <returns>Guid字符串</returns>        private static string GetCollectionItemIndex(string collectionIndexFieldName)        {            Queue<string> previousIndices = (Queue<string>)HttpContext.Current.Items[collectionIndexFieldName];            if (previousIndices == null)            {                HttpContext.Current.Items[collectionIndexFieldName] = previousIndices = new Queue<string>();                string previousIndicesValues = HttpContext.Current.Request[collectionIndexFieldName];                if (!string.IsNullOrWhiteSpace(previousIndicesValues))                {                    foreach (string index in previousIndicesValues.Split(','))                    {                        previousIndices.Enqueue(index);                    }                }            }            return previousIndices.Count > 0 ? previousIndices.Dequeue() : Guid.NewGuid().ToString();        }    }}

@{    ViewBag.Title = "RealGoTo";    Layout = "~/Views/Shared/_Layout.cshtml";}<h2>RealGoTo</h2>@Html.ActionLink("回到表单页","Index","Home")