省级三联动

来源：互联网发布：天津落户人才引进知乎编辑：程序博客网时间：2024/04/29 15:24

public partial class 省市县三级联动 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
               Download();
            }

        }
        string constr = "data source=.;initial catalog=liandong;user id=sa;pwd=7777777";

        protected void Download()
       {

           SqlConnection conn = new SqlConnection(constr);
           conn.Open();
           SqlCommand cmd = new SqlCommand();
           cmd.Connection = conn;
           cmd.CommandText = "select proID,proName from T_Promary";
           SqlDataAdapter adapter = new SqlDataAdapter(cmd);
            DataTable dt=new DataTable();
            adapter.Fill(dt);
            DropDownList1.DataSource = dt;
            DropDownList1.DataTextField = "proName";
            DropDownList1.DataValueField = "proId";
            DropDownList1.DataBind();

            cmd.Dispose();
            conn.Dispose();

       }
        string tiaojian1 = string.Empty;
        string tiaojian2 = string.Empty;
        protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
        {
            tiaojian1 = DropDownList1.SelectedValue;
            SqlConnection conn = new SqlConnection(constr);
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = "select cityID,cityName from T_City where proID=@tiaojian1 ";
            cmd.Parameters.AddWithValue("@tiaojian1", tiaojian1);
            SqlDataAdapter adapter = new SqlDataAdapter(cmd);
            DataTable dat = new DataTable();
            adapter.Fill(dat);
            DropDownList2.DataSource = dat;
            DropDownList2.DataTextField = "cityName";
            DropDownList2.DataValueField = "cityID";
            DropDownList2.DataBind();
            cmd.Dispose();
            conn.Dispose();
        }

        protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
        {
            tiaojian2 = DropDownList2.SelectedValue;
            SqlConnection conn = new SqlConnection(constr);
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = "select ctiyid,countyname,countyid from county where ctiyid=@tiaojian2 ";
            cmd.Parameters.AddWithValue("@tiaojian2", tiaojian2);
            SqlDataAdapter adapter = new SqlDataAdapter(cmd);
            DataTable data = new DataTable();
            adapter.Fill(data);
            DropDownList3.DataSource = data;
            DropDownList3.DataTextField = "countyname";
            DropDownList3.DataValueField = "countyid";
            DropDownList3.DataBind();
            cmd.Dispose();
            conn.Dispose();
        }
    }
}