如何把DropDownList的空白值放在最前面
我如何把一个空白值放在最前面 txtCityName.Items.Add(new ListItem("", ""));   
SqlConnection conn = new SqlConnection(@"uid=sa; pwd=123456; server=OURWAY-PC011\WANGHUA;database=tudi");
   SqlCommand cmd = new SqlCommand("select * from AADA02TB", conn);
   SqlDataAdapter adpt = new SqlDataAdapter(cmd);
   DataTable dtable = new DataTable();
   adpt.Fill(dtable);
   txtCityName.DataSource = dtable;
   txtCityName.DataTextField = "CityName";
   txtCityName.DataValueField = "CityCode";
   txtCityName.DataBind();
   adpt.Dispose();
   cmd.Dispose();
   conn.Close();
   txtCityName.Items.Add(new ListItem("", ""));
------解决方案--------------------C# code
ddl.Items.Insert(0, new ListItem("Not Select", "-1"))