小数据二级联动-封装成一个二级联动部分视图

@using OP.WebUI.Areas.Stock.Models

@*约定如下：
    调用 SetViewBag_Rooms 方法设置 ViewBag.Rooms
*@

<div class="form-group">
    <label class="col-sm-3 control-label no-padding-right" for="form-field-1"> 所属库房</label>
    <div class="col-sm-9">
        <select  id="RoomId" name="RoomId" class="width-40 chosen-select  form-control" data-placeholder="所属库房">
            @foreach (Father father in (IEnumerable<Father>)ViewBag.Rooms)
            {
                if (father.Selected)
                {
                    <option selected="selected" id="option-@father.Id" value="@father.Id" childs="@father.GetOptionsMark()">@father.Name</option>
                }
                else
                {
                    <option id="option-@father.Id" value="@father.Id" childs="@father.GetOptionsMark()">@father.Name</option>
                }
            }
        </select>
    </div>
</div>
<div class="form-group">
    <label class="col-sm-3 control-label no-padding-right" for="form-field-1"> 楼层</label>
    <div class="col-sm-9">
        <select id="FloorId" name="FloorId" class="width-40 chosen-select form-control" data-placeholder="楼层"></select>
    </div>
</div>

<script type="text/javascript">
    var room = $("#RoomId");
    room.change(function () {
        debugger;
        var roomId = $(this).val();
        loadChild(roomId);
    });
    function loadChild(roomId) {
        if (!roomId) {
            $("#FloorId").html("");
            return;
        }
        var childs = $("#option-" + roomId).attr("childs");
        $("#FloorId").html(childs);
    }
    loadChild(room.val());
</script>

using System.Collections.Generic;
using System.Text;

namespace OP.WebUI.Areas.Stock.Models
{
    public sealed class Father : Item
    {
        public IEnumerable<Child> Items { get; set; }

        /// <summary>
        /// 获取下拉选项标记
        /// </summary>
        /// <returns></returns>
        public string GetOptionsMark()
        {
            StringBuilder sb = new StringBuilder();
            foreach (var item in Items)
            {
                if (item.Selected)
                {
                    sb.Append("<option selected="selected" value="" + item.Id + "">" + item.Name + "</option>");
                }
                else
                {
                    sb.Append("<option value="" + item.Id + "">" + item.Name + "</option>");
                }
            }
            return sb.ToString();
        }
    }

    public sealed class Child : Item
    {
    }

    public abstract class Item
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public bool Selected { get; set; }
    }
}

//viewbag 调用示例
//rooms 是 父实体集合 floorsCatch 是子实体数据源
// on room.id = floor.roomid
var roomIds = rooms.Select(m => m.Id);
            var floorsCatch = _floorService.Value.GetFloors(roomIds);
            ViewBag.Rooms = rooms.Select(m => new Father
            {
                Id = m.Id,
                Name = m.Name,
                Selected = m.Id == selectedRoomId,
                Items = floorsCatch.Where(n => n.RoomId == m.Id && n.IsEnable == true)
                .Select(n => new Child { Id = n.Id, Name = n.Name, Selected = n.Id == selectedFloorId })
            });