我正在处理用户需要填写一些信息并最终通过复选框选择 1 个或多个客户的页面。
客户列表是IEnumerable<Customer>我传递给我的模型的。我将如何使用创建复选框列表.CheckBoxFor()？
最后，我希望能够验证是否至少选择了 1 个复选框。
Request 是保存用户输入信息的对象。
<% foreach (var customer in Model.Request.Customers) { %>
<%= Html.CheckBoxFor(/* customer */) %>
<% } %>
谁能指出我正确的方向？还是我对这一切都错了？
您可以创建一个自定义 html 扩展类并重载 CheckBoxFor 方法，如下所示。该方法将 metadata.Model 评估为传递给它的值（如美国州）。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
....
}
示例假设一个键值对通用列表
<% foreach (var element in UnitedStatesDictionary())
{ %>
<%= Html.CheckBoxFor(model => model.State, null, element.Key) %><%= element.Value %><br />
<% } %>
HtmlExtensions.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));
}
}
在此期间，这是我要完成的代码的美国列表：
/// <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() 扩展方法旨在编辑模型的布尔类型属性。您想使用它从 IEnumerable 集合中选择一些对象。这是错的。
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
}
我为此使用了一个助手类。这真的很简单。使用助手类，您可以使用 SelectList 并将其放入助手中，就像您对下拉列表所做的那样。
在“Helpers”文件夹中，我有 Checkboxlist.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(" " + 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();
}
}
我使用每个人都应该拥有的 ToSelectList 扩展。
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>
这个怎么运作：
我从已选择用户的数据库中获取值，获取他们的 id 并将其提供给方法 MvcApplication.lesgeverList(keys);
然后我把选择列表拿回来，把它放在视图数据中，当我打开它时，选定的人会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（所以选择了某些东西）然后我拆分我得到的变量，这是你在 SelectList 中给出的“值”。我遍历它们，将它们解析为整数，从数据库中获取具有解析 ID 的用户。通过计数，我查看它们是否存在于名为 _db.ProjectleiderProjectens 的“链接”表中
添加所有内容后，我使用 linq 语句一次性删除所有“未选择”的内容
_db.ProjectleiderProjectens.DeleteAllOnSubmit(_db.ProjectleiderProjectens.Where(p => p.Proj_ID == projID && !lgevers.Contains(p.LG_ID.ToString())));
我认为这很容易阅读。从中删除所有对象，获取所有对象的 ID 并检查哪些不在 ID 的 string[] 中
我必须说它工作得很好。如果您还有其他问题，请询问。
只需在客户端使用 jQuery 验证，然后在服务器端仔细检查自己，只需确保表单集合具有填充的值。
您的 for 循环没有任何问题。