protected void ddlcountry_SelectedIndexChanged(object sender, EventArgs e) { MyBL objbl = new MyBL(); // DataSet ds = new DataSet(); // SqlDataReader dr = objbl.getbyid(); //MyEL objel = new MyEL(); List <MyEL> lstel = new List <MyEL>(); // lstel = objbl.getbyid(ddlcountry.SelectedItem.Text); DataSet ds = objbl.getbyid(ddlcountry.SelectedItem.Text); ddlstate.DataSource = ds; ddlstate.DataValueField = "Id"; ddlstate.DataTextField = "State_Name"; ddlstate.DataBind(); }