Hello Quang,

Thank you for your patience!

Please refer to the attached sample.

The sample demonstrates how to setup cascading combo using mvc with initial selected items.

Let me know if you need further assistance.

the combobox can't select by value if I I get json data like this

 public ActionResult get_all_khu_vuc()
        {


            string strSQL = "select rtrim(MaKhuVucUT) as MaKhuVucUT, (rtrim(MaKhuVucUT) + ' | ' + TenKhuVucUT) as TenKhuVucUT  from DM_TS_KhuVucUuTien order by MaKhuVucUT asc";
            var data = SqlMapper.Query(this.cn, strSQL).ToList();

            return this.Json(data, JsonRequestBehavior.AllowGet);
        }

it work If I use js file and declare

var data_khu_vuc = [
                      { "ma_khu_vuc": "01",  "ten_khu_vuc": "01 | Khu vực 1" },            
                      { "ma_khu_vuc": "02",   "ten_khu_vuc": "02 | Khu vực 2" },
                      { "ma_khu_vuc": "03",  "ten_khu_vuc" :"03 | Khu vực 3" }
                      
                ];        

It's ok, I can set selected items in view by javascript here is my code:

$('#combo').igCombo({ initialSelectedItems: [{ index: 0 }] });

but my problem is I can't figure out how to set selected combobox with value (not index) from code behind in controller and return it to view.

Can I use combobox like this : List items = new List() and have selected if compare = true on value

foreach (countryModels)

items.Add(new SelectListItem
        {
            Text = ct.countryID.ToString().Trim() + " | " + ct.countryname.Trim()
            ,Value = ct.countryID.ToString().Trim()
            ,Selected = (ct.countryID.ToString().Trim() == CountryId)
        });

[controller]

ViewBag.List_Country=items;

[view]

Call combobox with have selected value from controller

Tk again