如何使用带验证的IEnumerable<t>的html.checkbox(list)

您可以创建一个自定义的HTML扩展类,并为如下方法重载checkbox。该方法将metadata.model计算为传递给它的值(如美国状态)。您可以从ControllerAction中的FormCollection获取复选框值:

public ActionResult Edit(FormCollection formCollection) 
{
    // Get the value(s)
    string checkBox = formCollection["State"];

    // perform validation
    ....
}

示例假定keyValuePair泛型列表

<% foreach (var element in UnitedStatesDictionary())
{ %>
<%= Html.CheckBoxFor(model => model.State, null, element.Key) %><%= element.Value  %><br />
<% } %>

HTML扩展.cs

using System;
using System.Linq;
using System.Linq.Expressions;
using System.Web.Mvc;
using System.Web.Routing;

    public static class HtmlExtensions
    {
        /// <summary>
        /// Checks the box for.
        /// </summary>
        /// <typeparam name="TModel">The type of the model.</typeparam>
        /// <typeparam name="TValue">The type of the value.</typeparam>
        /// <param name="html">The HTML.</param>
        /// <param name="expression">The expression.</param>
        /// <returns>Checkbox</returns>
        public static MvcHtmlString CheckBoxFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression)
        {
            return CheckBoxFor(html, expression, new RouteDirection());
        }


        /// <summary>
        /// Checks the box for.
        /// </summary>
        /// <typeparam name="TModel">The type of the model.</typeparam>
        /// <typeparam name="TValue">The type of the value.</typeparam>
        /// <param name="html">The HTML.</param>
        /// <param name="expression">The expression.</param>
        /// <param name="htmlAttributes">The HTML attributes.</param>
        /// <returns>Checkbox</returns>
        public static MvcHtmlString CheckBoxFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, object htmlAttributes)
        {

            return CheckBoxFor(html, expression, htmlAttributes, "");
        }

        /// <summary>
        /// Checks the box for.
        /// </summary>
        /// <typeparam name="TModel">The type of the model.</typeparam>
        /// <typeparam name="TValue">The type of the value.</typeparam>
        /// <param name="html">The HTML.</param>
        /// <param name="expression">The expression.</param>
        /// <param name="htmlAttributes">The HTML attributes.</param>
        /// <param name="checkedValue">The checked value.</param>
        /// <returns>Checkbox</returns>
        public static MvcHtmlString CheckBoxFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, object htmlAttributes, string checkedValue)
        {

            ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
            string htmlFieldName = ExpressionHelper.GetExpressionText(expression);

            TagBuilder tag = new TagBuilder("input");
            tag.Attributes.Add("type", "checkbox");
            tag.Attributes.Add("name", metadata.PropertyName);
            if (!string.IsNullOrEmpty(checkedValue))
            {
                tag.Attributes.Add("value", checkedValue);
            }
            else
            {
                tag.Attributes.Add("value", metadata.Model.ToString());
            }

            if (htmlAttributes != null)
            {
                tag.MergeAttributes(new RouteValueDictionary(htmlAttributes));
            }

            if (metadata.Model.ToString() == checkedValue)
            {
                tag.Attributes.Add("checked", "checked");
            }
            return MvcHtmlString.Create(tag.ToString(TagRenderMode.SelfClosing));
        }
    }

当我在这里的时候,这是我的美国完成代码列表:

/// <summary>
/// United States dictionary.
/// </summary>
/// <returns>List of United States</returns>
public static List<KeyValuePair<string, string>> UnitedStatesDictionary()
{
    var arrList = new List<KeyValuePair<string, string>>();
    arrList.Add(new KeyValuePair<string, string>("AL", "Alabama"));
    arrList.Add(new KeyValuePair<string, string>("AK", "Alaska"));
    arrList.Add(new KeyValuePair<string, string>("AZ", "Arizona" ));
    arrList.Add(new KeyValuePair<string, string>("AR", "Arkansas" ));
    arrList.Add(new KeyValuePair<string, string>("CA", "California" ));
    arrList.Add(new KeyValuePair<string, string>("CO", "Colorado" ));
    arrList.Add(new KeyValuePair<string, string>("CT", "Connecticut" ));
    arrList.Add(new KeyValuePair<string, string>("DE", "Delaware" ));
    arrList.Add(new KeyValuePair<string, string>("DC", "District Of Columbia" ));
    arrList.Add(new KeyValuePair<string, string>("FL", "Florida" ));
    arrList.Add(new KeyValuePair<string, string>("GA", "Georgia" ));
    arrList.Add(new KeyValuePair<string, string>("HI", "Hawaii" ));
    arrList.Add(new KeyValuePair<string, string>("ID", "Idaho" ));
    arrList.Add(new KeyValuePair<string, string>("IL", "Illinois" ));
    arrList.Add(new KeyValuePair<string, string>("IN", "Indiana" ));
    arrList.Add(new KeyValuePair<string, string>("IA", "Iowa" ));
    arrList.Add(new KeyValuePair<string, string>("KS", "Kansas" ));
    arrList.Add(new KeyValuePair<string, string>("KY", "Kentucky" ));
    arrList.Add(new KeyValuePair<string, string>("LA", "Louisiana" ));
    arrList.Add(new KeyValuePair<string, string>("ME", "Maine" ));
    arrList.Add(new KeyValuePair<string, string>("MD", "Maryland" ));
    arrList.Add(new KeyValuePair<string, string>("MA", "Massachusetts" ));
    arrList.Add(new KeyValuePair<string, string>("MI", "Michigan" ));
    arrList.Add(new KeyValuePair<string, string>("MN", "Minnesota" ));
    arrList.Add(new KeyValuePair<string, string>("MS", "Mississippi" ));
    arrList.Add(new KeyValuePair<string, string>("MO", "Missouri" ));
    arrList.Add(new KeyValuePair<string, string>("MT", "Montana" ));
    arrList.Add(new KeyValuePair<string, string>("NE", "Nebraska" ));
    arrList.Add(new KeyValuePair<string, string>("NV", "Nevada" ));
    arrList.Add(new KeyValuePair<string, string>("NH", "New Hampshire" ));
    arrList.Add(new KeyValuePair<string, string>("NJ", "New Jersey" ));
    arrList.Add(new KeyValuePair<string, string>("NM", "New Mexico" ));
    arrList.Add(new KeyValuePair<string, string>("NY", "New York" ));
    arrList.Add(new KeyValuePair<string, string>("NC", "North Carolina" ));
    arrList.Add(new KeyValuePair<string, string>("ND", "North Dakota" ));
    arrList.Add(new KeyValuePair<string, string>("OH", "Ohio" ));
    arrList.Add(new KeyValuePair<string, string>("OK", "Oklahoma" ));
    arrList.Add(new KeyValuePair<string, string>("OR", "Oregon" ));
    arrList.Add(new KeyValuePair<string, string>("PA", "Pennsylvania" ));
    arrList.Add(new KeyValuePair<string, string>("RI", "Rhode Island" ));
    arrList.Add(new KeyValuePair<string, string>("SC", "South Carolina" ));
    arrList.Add(new KeyValuePair<string, string>("SD", "South Dakota" ));
    arrList.Add(new KeyValuePair<string, string>("TN", "Tennessee" ));
    arrList.Add(new KeyValuePair<string, string>("TX", "Texas" ));
    arrList.Add(new KeyValuePair<string, string>("UT", "Utah" ));
    arrList.Add(new KeyValuePair<string, string>("VT", "Vermont" ));
    arrList.Add(new KeyValuePair<string, string>("VA", "Virginia" ));
    arrList.Add(new KeyValuePair<string, string>("WA", "Washington" ));
    arrList.Add(new KeyValuePair<string, string>("WV", "West Virginia" ));
    arrList.Add(new KeyValuePair<string, string>("WI", "Wisconsin" ));
    arrList.Add(new KeyValuePair<string, string>("WY", "Wyoming" ));
    return arrList;
}

html.checkboxfor()扩展方法旨在 编辑 布尔类型的模型属性。您希望使用它从IEnumerable集合中选择一些对象。这是错误的。

正确的方法:

在视野中

<form action="/Customer/Process">
<% foreach (var customer in Model.Request.Customers)
   { %>
        <input type="checkbox" name="selectedId" value="<%= customer.id %>" />
        <%= customer.name %>
        <br/>
<% } %>
        <input type="submit"/>
</form>

在控制器中

public string Process(IEnumerable<Guid> selectedId)
{
    if (selectedId == null)
    {
        ModelState.AddModelError("selectedId", "Have to select at least one customer!");

        return View();
    }

    // do something with customers' ids
}

我用了一个助手类。真的很简单。使用helper类,您可以使用selectlist并将其放入helper中,就像使用DropDownfor一样。

在“helpers”文件夹中,我有checkbox list.cs

    using System;
    using System.Web.Mvc;
    using System.Collections.Generic;
    using System.Text;
    using System.Linq;

    namespace MVC2_NASTEST.Helpers {
        public static class CheckBoxListHelper {

            public static string CheckBoxList(this HtmlHelper helper, string name, IDictionary<string, string> items) {
                return CheckBoxList(helper, name, items, null, null);
            }

            public static string CheckBoxList(this HtmlHelper helper, string name, IDictionary<string, string> items, IDictionary<string, object> checkboxHtmlAttributes) {
                return CheckBoxList(helper, name, items, null, checkboxHtmlAttributes);
            }

            public static string CheckBoxList(this HtmlHelper helper, string name, IDictionary<string, string> items, IEnumerable<string> selectedValues) {
                return CheckBoxList(helper, name, items, selectedValues, null);
            }

            public static string CheckBoxList(this HtmlHelper helper, string name, IDictionary<string, string> items, IEnumerable<string> selectedValues, IDictionary<string, object> checkboxHtmlAttributes) {

                var selectListItems = from i in items
                                      select new SelectListItem {
                                          Text = i.Key,
                                          Value = i.Value,
                                          Selected = (selectedValues != null && selectedValues.Contains(i.Value))
                                      };

                return CheckBoxList(helper, name, selectListItems, checkboxHtmlAttributes);
            }

            public static string CheckBoxList(this HtmlHelper helper, string name, IEnumerable<SelectListItem> items) {
                return CheckBoxList(helper, name, items, null);
            }

            public static string CheckBoxList(this HtmlHelper helper, string name, IEnumerable<SelectListItem> items, IDictionary<string, object> checkboxHtmlAttributes) {
                var output = new StringBuilder();

                foreach (var item in items) {
                    output.Append("<div class=\"fields\"><label>");
                    var checkboxList = new TagBuilder("input");
                    checkboxList.MergeAttribute("type", "checkbox");
                    checkboxList.MergeAttribute("name", name);
                    checkboxList.MergeAttribute("value", item.Value);

                    // Check to see if it's checked
                    if (item.Selected)
                        checkboxList.MergeAttribute("checked", "checked");

                    // Add any attributes
                    if (checkboxHtmlAttributes != null)
                        checkboxList.MergeAttributes(checkboxHtmlAttributes);

                    checkboxList.SetInnerText(item.Text);
                    output.Append(checkboxList.ToString(TagRenderMode.SelfClosing));
                    output.Append("&nbsp; " + item.Text + "</label></div>");
                }

                return output.ToString();
            }
        }
    }

我的控制器中的代码:

    public static List<SelectListItem> lesgeverList() {
        return lesgeverList(-1);
    }

    public static List<SelectListItem> lesgeverList(int selectedID) {
        return lesgeverList(new int[] { selectedID });
    }

    public static List<SelectListItem> lesgeverList(int[] lg) {
        NASDataContext _db = new NASDataContext();
        var lesg = (from l in _db.Lesgevers
                    where l.LG_Naam != "leeg"
                    orderby l.LG_Naam, l.LG_Vnaam
                    select l).ToSelectList(m => m.LG_Naam + " " + m.LG_Vnaam, m => m.LG_ID.ToString(), m => lg.Contains(m.LG_ID));
        return lesg.ToList();
    }

    //
    // GET: /Projectleiders/Create

    public ActionResult Create(int projID) {
        ViewData["projNaam"] = getProject(projID).Proj_Kortenaam;
        int[] keys = (from p in _db.ProjectleiderProjectens
                      where p.Proj_ID == projID
                      from l in _db.Lesgevers
                      where p.LG_ID == l.LG_ID
                      select l.LG_ID).ToArray();

        ViewData["projleiders"] = MvcApplication.lesgeverList(keys);

        return toegankelijk(projID, null);
    }

    //
    // POST: /Projectleiders/Create

    [HttpPost]
    public ActionResult Create(FormCollection collection, int projID) {

        if (collection["lesgeverlist"] != null) {
            string[] lgevers = collection["lesgeverlist"].Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);
            List<ProjectleiderProjecten> lst = new List<ProjectleiderProjecten>();
            foreach (string s in lgevers) {
                ProjectleiderProjecten prl = new ProjectleiderProjecten();
                prl.LG_ID = int.Parse(s);
                prl.Proj_ID = projID;

                int count = (from m in _db.ProjectleiderProjectens
                             where m.LG_ID == prl.LG_ID && m.Proj_ID == prl.Proj_ID
                             select m).Count();

                if (count <= 0) {
                    //deze bestaat nog niet
                    lst.Add(prl);
                }
            }
            //var test = _db.ProjectleiderProjectens.Where(p => p.Proj_ID == projID && !lgevers.Contains(p.LG_ID.ToString())).ToList();

            _db.ProjectleiderProjectens.DeleteAllOnSubmit(_db.ProjectleiderProjectens.Where(p => p.Proj_ID == projID && !lgevers.Contains(p.LG_ID.ToString())));

            _db.ProjectleiderProjectens.InsertAllOnSubmit(lst);
            _db.SubmitChanges();

            return RedirectToAction("Index");
        } else {

            ModelState.AddModelError("lesgeverlist", "Je hebt geen lesgevers geselecteerd");

            ViewData["projleiders"] = MvcApplication.lesgeverList();
            ViewData["projNaam"] = getProject(projID).Proj_Kortenaam;
            return View();
        }
    }

我使用toselectlist扩展名,这是每个人都应该拥有的。

public static class VSKOExtensions {
    public static IList<SelectListItem> ToSelectList<T>(this IEnumerable<T> itemsToMap, Func<T, string> textProperty, Func<T, string> valueProperty, Predicate<T> isSelected) {
        var result = new List<SelectListItem>();

        foreach (var item in itemsToMap) {
            result.Add(new SelectListItem {
                Value = valueProperty(item),
                Text = textProperty(item),
                Selected = isSelected(item)
            });
        }
        return result;
    }
}

我的创建视图(同时也是一个编辑视图)中的代码非常简单

    <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MVC2_NASTEST.Models.ProjectleiderProjecten>" %>
    <%@ Import Namespace="MVC2_NASTEST.Helpers" %>

    <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
        Create
    </asp:Content>

    <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

        <h2>Koppel projectleider voor
            <%= ViewData["projNaam"].ToString() %></h2>

        <% using (Html.BeginForm()) {%>
            <%= Html.ValidationSummary(true) %>

            <fieldset>
                <legend>Fields</legend>

                <div class="editor-label">
                    <%= Html.Label("Lesgevers")%>
                </div>
                <div class="editor-field">
                    <%= Html.CheckBoxList("Lesgeverlist", ViewData["projleiders"] as List<SelectListItem>)%>
                    <%= Html.ValidationMessage("Lesgeverlist")%>
                </div>

                <p>
                    <input type="submit" value="Create" />
                </p>
            </fieldset>

        <% } %>

        <div>
            <%= Html.ActionLink("Back to List", "Index") %>
        </div>

    </asp:Content>

它是如何工作的:

我从已经选择的用户的数据库中获取值,获取他们的ID,并将其赋给mvcaplication.lesgeverlist(keys)方法;

然后我返回选择列表,将其放在视图数据中,当我打开它时,所选人员在我的视图中被选中。然后,当我更改一些框并保存它时,我检查集合是否不为空(因此选择了一些内容),然后我拆分返回的变量,这些变量是您在SelectList中给出的“值”。我通过它们,将它们解析为int,从db中获取用户及其解析ID。通过计数,我查看它们是否存在于“链接”表中,该表称为db.projectleiderprojectens

当全部添加后,我将使用LINQ语句在1次内删除所有未选中的

   _db.ProjectleiderProjectens.DeleteAllOnSubmit(_db.ProjectleiderProjectens.Where(p => p.Proj_ID == projID && !lgevers.Contains(p.LG_ID.ToString())));

我觉得它可读性很好。从中删除所有对象,获取所有对象的ID,并检查哪些对象不在ID的字符串[]中

我得说,它工作得相当好。如果你还有什么问题,就问吧。

只需在客户端使用jquery validate,然后在服务器端对自己进行双重检查,只需确保表单集合中填充了一个值。

你的for循环没有问题。