HTML代码 <asp:DropDownList ID="ddlWarehouseIds" runat="server" CssClass="ddl"></asp:DropDownList><input type="hidden" name="<%#Eval("WarehouseNames")%>" id="hid_<%#Eval("UserID")%>"  value=" <%#Eval("WarehouseIds")%>" />

Mutiselect 插件地址  http://www.cnblogs.com/xinchuang/archive/2013/05/24/3096757.html

//设置选中项 ===========================================================

  1  //初始化
  2         $(function()
  3         {
  4             $(".ddl").multiselect({
  5                 noneSelectedText: "--请选择仓库--",
  6                 checkAllText: "全选",
  7                 uncheckAllText: '全不选',
  8                 selectedList:4
  9                 //header:"7"
 10             });
 11         });
 12         //设置默认选中项
 13         $(function()
 14         {
 15             $("#TableList tr td[id]").each(function()
 16              {
 17                   var objs=$(this).children();
 18                   var warehouses=objs[2];
 19                   var warehouseNames=$(warehouses).attr("name");
 20                   var warehouseids=$(warehouses).val();
 21                   //展示给用户选择的仓库
 22                   var spans=$(objs[1]).children();
 23                   if(warehouseNames.length>0)
 24                   {
 25                     $(spans[1]).text(warehouseNames);
 26                   }
 27                   else
 28                   {
 29                     $(spans[1]).text("--请选择仓库--");
 30                   }
 31                   //点击文本框 选中默认项
 32                   var ids=warehouseids.split(",");
 33                   $(objs[1]).click(function()
 34                   {
 35                       var div=  $("#UploadForm").nextAll("[name]");//手动改的源码 点击文本框时 给下拉框添加个属性 以标识当前修改的下拉框
 36                       //alert(div.attr("name"));
 37                       var ul=$(div).children(":last-child");
 38                      // alert (ul.attr("class"));
 39                       var lis=ul.children();
 40                       //alert(lis.length);
 41
 42                       //清空默认选中值
 43                       $(lis).each(function(){
 44                             //获取lable
 45                             var me=$(this).children();
 46                            // alert(me.length);
 47                            // alert (me.attr("class"));
 48                            //获取input标签
 49                           var input=me.children(":first-child");
 50                           //删除默认属性
 51                           input.removeAttr("checked");
 52                           input.removeAttr("aria-selected");
 53                       });
 54
 55
 56                       for (var j=0;j<ids.length;j++)
 57                       {
 58                           for (var i=0;i<lis.length;i++)
 59                           {
 60                             //获取lable
 61                             var me=$(lis[i]).children();
 62                            // alert(me.length);
 63                            // alert (me.attr("class"));
 64                             //获取input标签
 65                             var input=me.children(":first-child");
 66                             //获取input的值
 67                             var inputValue=input.val();
 68
 69                            // alert(inputValue)
 70                             //删除默认属性
 71                              //input.removeAttr("checked");
 72                              //input.removeAttr("aria-selected");
 73                             //重新 绑定数据库中读取的数据
 74                             if(inputValue*1==ids[j]*1)
 75                             {
 76                                 $(input).prop("checked","checked");
 77                                 $(input).attr("aria-selected","true");
 78                             }
 79                           }
 80                       }
 81                   });
 82              })
 83         })
 84         //保存=========================================
 85         function SaveUserWarehouse(userId,obj)
 86         {
 87
 88             var me =$(obj).parent().prev().children();
 89             var valuestr = me.multiselect("getChecked").map(function () {
 90                 return this.value;
 91             }).get();
 92             //alert(valuestr);
 93             // alert(typeof(valuestr));
 94             //var me =$(obj).parent().prev().children();
 95             //var valuestr = me.multiselect("MyValues");
 96              $.ajax({
 97                 type: "POST",
 98                 url: "/B2C/handlers/Warehouse/SaveUserWarehouse.ashx",
 99                 data: { "warehouseids":valuestr.toString(),"userId":userId},
100                 success: function(msg)
101                 {
102                     if(msg =="ok")
103                     alert ("保存成功!");
104                     reload();
105                 },
106                 error: function() {
107                     alert("请求异常，请稍后再试！");
108                 }
109             });
110         }