[Solved] ASP.Net MVC Error: cannot convert from 'string' to 'System.Collections.Generic.IEnumerable'

Hi,

I need populate a DropDownList from values obtained from a database table using MySql database and view model using ASP NET MVC.

After populate a DropDownList I need filter WebGrid using the value selected on DropDownList. 

But I have this error

CS1503: Argument 1: cannot convert from 'string' to 'System.Collections.Generic.IEnumerable'

Help me to do it.

My code below

model

public List<SelectListItem> CityUO_List { get; set; }
public List<PersonModel> CityUO { get; set; }

controller

    public static List<SelectListItem> PopulateDates(string UserUO)
    {
        List<SelectListItem> items = new List<SelectListItem>();
        string cs = ConfigurationManager.ConnectionStrings["cn"].ConnectionString;

        using (MySqlConnection con = new MySqlConnection(cs))
        {
            string sql = @String.Format(" SELECT City FROM `dotable`WHERE UOR = @UOR; ");

            using (MySqlCommand cmd = new MySqlCommand(sql))
            {
                cmd.Parameters.AddWithValue("@UOR", System.Web.HttpContext.Current.Session["UserUO"]);
                cmd.Connection = con;
                con.Open();
                using (MySqlDataReader sdr = cmd.ExecuteReader())
                {
                    while (sdr.Read())
                    {
                        items.Add(new SelectListItem
                        {
                            Text = sdr["City"].ToString(),
                            Value = sdr["City"].ToString()
                        });
                    }
                }

                cmd.Connection.Close();
            }
        }

        return items;
    }

    public ActionResult RecoveryAll()
    {
        PersonModel model = new PersonModel();
        model.CityUO_List = PopulateDates(null);
        return View(model);
    }

    [HttpPost]
    public ActionResult RecoveryAll(PersonModel model)
    {
        model.CityUO_List = PopulateDates(???);
        return View(model);
    }

view

@model Ins.Models.PersonModel

@{
   WebGrid webGrid = new WebGrid(source: Model.CityUO, canPage: true, canSort: false, rowsPerPage: 10);
 }

@using (Html.BeginForm("Index", "Home", FormMethod.Post, new { @Id = "WebGridForm" }))
{
   @Html.DropDownList("City", Model.CityUO_List, "Select City", new { @id = "ddlCity" })
}