两个droplist，droplist2中的内容根据droplist1改变而改变
droplist1是数据库中读出的，根据droplist1中的选择，droplist2从数据库中选出内容，并填充代码如下
  protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
  {

  int fid = Convert.ToInt32(DropDownList1.SelectedValue);


  SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ZZW_OLConnectionString"].ConnectionString);
  conn.Open();
  SqlDataAdapter myCommand=new SqlDataAdapter("SELECT * from XX_city where City_province='" + fid + "'",conn); 
  DataSet ds=new DataSet(); 
  myCommand.Fill(ds); 
  DataView source=new DataView(ds.Tables[0]);
  DropDownList2.DataValueField = ds.Tables[0].Columns[0].ToString();

  DropDownList2.DataTextField = ds.Tables[0].Columns[1].ToString();
  DropDownList2.DataSource=source; 
  DropDownList2.DataBind(); 

  }


但是我单击确定按钮后，要将droplist2中的内容传到另一个页面 无法实现，无论我选择哪项，droplist2传过去的内容都是一样的。传值语句是：
  protected void Button1_Click(object sender, EventArgs e)
  {
   
  Response.Cookies["cityId"].Value =DropDownList2.SelectedValue;
  Response.Cookies["cityName"].Value = DropDownList2.SelectedItem.Text;
  Response.Redirect("index.aspx");
  }

------解决方案--------------------
你是不是将DropDownList2的AutoPostBack属性也设置成了True了啊？？？
------解决方案--------------------
HttpCookie id = new HttpCookie("cityId",DropDownList2.SelectedValue);
Response.Cookies.Add(id)

HttpCookie txt = new HttpCookie("cityId",DropDownList2.SelectedItem.Text);
Response.Cookies.Add(txt )
------解决方案--------------------
Response.Cookies和Request.Cookies是有区别的，
Response.Cookies只能当前页面使用。参见
http://dotnet.aspx.cc/file/Difference-Response-Cookies-Request-Cookies.aspx