C#请问如何控制器如何获取选择值进行有条件查询，本人初学，希望大神帮忙！希望写详细点，感谢！

Question

public class C_F_BuyCertController : Controller
{
    public ActionResult Getlist( )
    {
        string ConnectString = "data source=172.16.60.144/orcl;User Id=yzd4hub;Password=yzd4hub;";
        OracleConnection conn = new OracleConnection(ConnectString);//Data Source后面跟数据库的名字，User ID为用户名，Password为密码
        try
        {
            conn.Open();
            string province=Request["province"];
            string city = Request.Form["city"];
            string county = Request.Form["county"];
            string sql = "select a.c_id,a.buy_id from c_f_buycert a where a.province=:province and a.city=:city and a.county=:county";
            OracleCommand cmd = new OracleCommand(sql, conn);
            OracleDataAdapter oda = new OracleDataAdapter(cmd);
            DataTable dt = new DataTable();
            oda.Fill(dt);
            List<C_F_BuyCert> modellist = new List<C_F_BuyCert>();
            int rowscount = dt.Rows.Count;
            if (rowscount > 0)
            {
                C_F_BuyCert buycert;
                for (int n = 0; n < rowscount; n++)
                {
                    buycert = new C_F_BuyCert();
                    buycert.C_Id = dt.Rows[n]["C_ID"].ToString();
                    buycert.Buy_Id = dt.Rows[n]["BUY_ID"].ToString();
                    modellist.Add(buycert);
                }
            }
            ViewData.Add("list", modellist);
            return View();
        }
        finally
        {
            conn.Close();
        }
    }
}

}

@model IEnumerable
@{ViewBag.Title = "Getlist";}

查询购买事实

所在省：

所在市：

所在区县：

@{ var list = ViewData["list"] as List; foreach (var item in list) { } }

C_Id	Buy_Id
@item.C_Id	@item.Buy_Id

Answer 1

楼主您好 请问是要实现 选了X省 就只显示X省下面的数据，
在X省下选了Y市就只显示X省Y市下面的数据吗？