using System;using System.Collections.Generic;using System.Linq;using System.Linq.Expressions;using System.Text;using System.Web;using System.Web.Mvc;namespace Demo{    public static class CheckBoxListHelper    {        public static MvcHtmlString CheckBoxList(this HtmlHelper helper, string name, bool isHorizon = true)        {            return CheckBoxList(helper, name, helper.ViewData[name] as IEnumerable<SelectListItem>, new { }, isHorizon);        }        public static MvcHtmlString CheckBoxList(this HtmlHelper helper, string name, IEnumerable<SelectListItem> selectList, bool isHorizon = true)        {            return CheckBoxList(helper, name, selectList, new { }, isHorizon);        }        public static MvcHtmlString CheckBoxListFor<TModel, TProperty>(this HtmlHelper helper, Expression<Func<TModel, TProperty>> expression, IEnumerable<SelectListItem> selectList, bool isHorizon = true)        {            string[] propertys = expression.ToString().Split(".".ToCharArray());            string id = string.Join("_", propertys, 1, propertys.Length - 1);            string name = string.Join(".", propertys, 1, propertys.Length - 1);            return CheckBoxList(helper, id, name, selectList, new { }, isHorizon);        }        public static MvcHtmlString CheckBoxList(this HtmlHelper helper, string name, IEnumerable<SelectListItem> selectList, object htmlAttributes, bool isHorizon = true)        {            return CheckBoxList(helper, name, name, selectList, htmlAttributes, isHorizon);        }        public static MvcHtmlString CheckBoxList(this HtmlHelper helper, string id, string name, IEnumerable<SelectListItem> selectList, object htmlAttributes, bool isHorizon = true)        {            IDictionary<string, object> HtmlAttributes = HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes);            HashSet<string> set = new HashSet<string>();            List<SelectListItem> list = new List<SelectListItem>();            string selectedValues = (selectList as SelectList).SelectedValue =http://www.mamicode.com/= null ? string.Empty : Convert.ToString((selectList as SelectList).SelectedValue);            if (!string.IsNullOrEmpty(selectedValues))            {                if (selectedValues.Contains(","))                {                    string[] tempStr = selectedValues.Split(‘,‘);                    for (int i = 0; i < tempStr.Length; i++)                    {                        set.Add(tempStr[i].Trim());                    }                }                else                {                    set.Add(selectedValues);                }            }            foreach (SelectListItem item in selectList)            {                item.Selected = (item.Value != null) ? set.Contains(item.Value) : set.Contains(item.Text);                list.Add(item);            }            selectList = list;            HtmlAttributes.Add("type", "checkbox");            HtmlAttributes.Add("id", id);            HtmlAttributes.Add("name", name);            HtmlAttributes.Add("style", "border:none;");            StringBuilder stringBuilder = new StringBuilder();            foreach (SelectListItem selectItem in selectList)            {                IDictionary<string, object> newHtmlAttributes = HtmlAttributes.DeepCopy();                newHtmlAttributes.Add("value", selectItem.Value);                if (selectItem.Selected)                {                    newHtmlAttributes.Add("checked", "checked");                }                TagBuilder tagBuilder = new TagBuilder("input");                tagBuilder.MergeAttributes<string, object>(newHtmlAttributes);                string inputAllHtml = tagBuilder.ToString(TagRenderMode.SelfClosing);                string containerFormat = isHorizon ? @"<label> {0}  {1}</label>" : @"<p><label> {0}  {1}</label></p>";                stringBuilder.AppendFormat(containerFormat,                   inputAllHtml, selectItem.Text);            }            return MvcHtmlString.Create(stringBuilder.ToString());        }        private static IDictionary<string, object> DeepCopy(this IDictionary<string, object> ht)        {            Dictionary<string, object> _ht = new Dictionary<string, object>();            foreach (var p in ht)            {                _ht.Add(p.Key, p.Value);            }            return _ht;        }    }}