OPTGROUP下拉支持MVC - 问题与模型绑定 [英] Optgroup drop-down support in MVC - Problems with Model Binding

问题描述

我想知道如果任何人都可以在这个问题上。

I wonder if anyone can shed some light on this problem..

我得选择一个人的种族选项组下拉 - 但它不是存储在模型中值

I've got an option group drop-down for selecting a person's ethnicity – however it’s not storing the value in the model.

视图模型

    [UIHint("EthnicOriginEditorTemplate")]
    [DisplayName("Question 6: Ethnic Origin")]
    public int EthnicOrigin { get; set; }

助手：GroupDropList.Cs

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

namespace Public.Helpers
{
    public static class GroupDropListExtensions
    {
        public static string GroupDropList(this HtmlHelper helper, string name, IEnumerable<GroupDropListItem> data, int SelectedValue, object htmlAttributes)
        {
            if (data == null && helper.ViewData != null)
                data = helper.ViewData.Eval(name) as IEnumerable<GroupDropListItem>;
            if (data == null) return string.Empty;

            var select = new TagBuilder("select");

            if (htmlAttributes != null)
                select.MergeAttributes(new RouteValueDictionary(htmlAttributes));

            select.GenerateId(name);

            var optgroupHtml = new StringBuilder();
            var groups = data.ToList();
            foreach (var group in data)
            {
                var groupTag = new TagBuilder("optgroup");
                groupTag.Attributes.Add("label", helper.Encode(group.Name));
                var optHtml = new StringBuilder();
                foreach (var item in group.Items)
                {
                    var option = new TagBuilder("option");
                    option.Attributes.Add("value", helper.Encode(item.Value));
                    if (SelectedValue != 0 && item.Value == SelectedValue)
                        option.Attributes.Add("selected", "selected");
                    option.InnerHtml = helper.Encode(item.Text);
                    optHtml.AppendLine(option.ToString(TagRenderMode.Normal));
                }
                groupTag.InnerHtml = optHtml.ToString();
                optgroupHtml.AppendLine(groupTag.ToString(TagRenderMode.Normal));
            }
            select.InnerHtml = optgroupHtml.ToString();
            return select.ToString(TagRenderMode.Normal);
        }
    }

    public class GroupDropListItem
    {
        public string Name { get; set; }
        public List<OptionItem> Items { get; set; }
    }

    public class OptionItem
    {
        public string Text { get; set; }
        public int Value { get; set; }
    }
}

这是我的EditorTemplate

<%@ Import Namespace="Public.Helpers"%>
<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<int>"%>

<%=Html.GroupDropList("EthnicOrigin",
                                 new[]
                                    {                                        
                                        new GroupDropListItem
                                             {
                                                 Name = "Ethnicity",
                                                 Items = new List<OptionItem>
                                                         {
                                                             new OptionItem {Value = 0, Text = "Please Select"}
                                                         }
                                             },

                                        new GroupDropListItem
                                             {
                                                 Name = "a) White",
                                                 Items = new List<OptionItem>
                                                         {
                                                             new OptionItem {Value = 1, Text = "British"},
                                                             new OptionItem {Value = 2, Text = "Irish"},
                                                             new OptionItem {Value = 3, Text = "Other White (Please specify below)"}
                                                         }
                                             },

                                         --snip

                                     }, Model, null)%>

并在视图中，我引用它为：

<%=Html.EditorFor(x => x.EthnicOrigin, "EthnicOriginEditorTemplate")%>

但它没有经过选择的价值到模型......有没有人遇到类似的问题......许多在此先感谢一些三分球。

However it's not passing through the selected Value into the model... has anyone experienced similar problems... many thanks in advance for some pointers.

推荐答案

您选择不具有名称属性，所以当你提交表单选择的值不会被发送到服务器。您需要添加一个名字：

Your select doesn't have a name attribute and so when you submit the form the selected value is not sent to the server. You need to add a name:

select.GenerateId(name);
select.MergeAttribute("name", name);

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