关于DropDownList

前台绑定：
<asp:DropDownList ID="dplENTERPRISE_PROV" runat="server" onchange="ddlPchange();" Width="206px" CssClass="yh"

Font-Size="12px"></asp:DropDownList>
<asp:DropDownList ID="dplENTERPRISE_CITY" runat="server" onchange="ddlCchange();" Width="206px" CssClass="yh"

Font-Size="12px"></asp:DropDownList>
<asp:DropDownList ID="dplENTERPRISE_AREA" runat="server" onchange="ddlAreaChange();"  Width="206px"

CssClass="yh" Font-Size="12px"></asp:DropDownList>

 <script language="javascript" type="text/javascript">
        function ddlPchange() {
            var ddlPROVINCE = document.getElementById("<%=dplENTERPRISE_PROV.ClientID %>");
            var Value = ddlPROVINCE.options[ddlPROVINCE.selectedIndex].value;
            var ddlCITY = document.getElementById("<%=dplENTERPRISE_CITY.ClientID %>");
           
            for(var i=0;i<ddlCITY.options.length;i++)
            {
                ddlCITY.options.remove(i);
                i--;
            }
           
           
            //清楚区域信息
              var dplArea = document.getElementById("<%=dplENTERPRISE_AREA.ClientID %>");
           
            for(var i=0;i<dplArea.options.length;i++)
            {
               dplArea.options.remove(i);
                i--;
            }
           
           
            var ddlArea = document.getElementById("<%=ddlArea.ClientID %>");
           
            for (var j=0;j<ddlArea.options.length;j++)
            {
                if(Value == ddlArea.options[j].value)
                {
                    var text = ddlArea.options[j].innerHTML;
                    var arr=text.split("~~");
                    var newOption = document.createElement("OPTION");
                    newOption.value = arr[0];
                    newOption.text = arr[1];
                    ddlCITY.options.add(newOption);
                }
            }
            if(ddlCITY.options.length>0)
            {
                ddlCITY.options[0].selected=true;
                document.getElementById("txtvalue").value = ddlCITY.options[0].value;
            }
           
           
             var dplArea = document.getElementById("<%=dplENTERPRISE_AREA.ClientID %>");
              var optionInit = document.createElement("OPTION");
             //optionInit.value = '';
             optionInit.text = '请选择...';
             dplArea.options.add(optionInit);
           
　　　　}
　　　　
　　　　function ddlCchange()
　　　　{
　　　　    var ddlCITY = document.getElementById("<%=dplENTERPRISE_CITY.ClientID %>");
　　　　    document.getElementById("txtvalue").value = ddlCITY.options[ddlCITY.selectedIndex].value;
　　　　    var Value = ddlCITY.options[ddlCITY.selectedIndex].value;
　　　　   
　　　　    //清楚区域信息
　　　　    var dplArea = document.getElementById("<%=dplENTERPRISE_AREA.ClientID %>");
           
            for(var i=0;i<dplArea.options.length;i++)
            {
               dplArea.options.remove(i);
                i--;
            }
           
            //绑定区域信息
            var dplAllArea = document.getElementById("<%=dplAllArea.ClientID %>");
            var optionInit = document.createElement("OPTION");
             //optionInit.value = '';
             optionInit.text = '请选择...';
             dplArea.options.add(optionInit);
           
            for (var j=0;j<dplAllArea.options.length;j++)
            {
                if(Value == dplAllArea.options[j].value)
                {
                    var text = dplAllArea.options[j].innerHTML;
                    var arr=text.split("~~");
                    var newOption = document.createElement("OPTION");
                    newOption.value = arr[0];
                    newOption.text = arr[1];
                    dplArea.options.add(newOption);
                }
            }
           
      
            if(dplArea.options.length>0)
            {
                dplArea.options[0].selected=true;
                document.getElementById("txtArea").value = dplArea.options[0].value;
            }
　　　　   
　　　　}
　　　　
　　　　function ddlAreaChange()
　　　　{
　　　　    var dplArea = document.getElementById("<%=dplENTERPRISE_AREA.ClientID %>");
　　　　    document.getElementById("txtArea").value = dplArea.options[dplArea.selectedIndex].value;
　　　　}
　　　　
        </script>
        <asp:DropDownList ID="ddlArea" runat="server">
         </asp:DropDownList>
         <asp:DropDownList ID="dplAllArea" runat="server">
         </asp:DropDownList>
          <input id="txtvalue" name="txtvalue" type="hidden" value="" />
          <input id="txtArea" name="txtArea" type="hidden" value="" />

后台绑定：
 

public partial class Regqiuzhi  : BasePage
{
    protected void Page_Load(object sender, EventArgs e)
    {
        RoleBLL role = new RoleBLL();
        if (!IsPostBack)
        {
            bindDDL();
            RoleBLL rolebll = new RoleBLL();
            rolebll.Bind_dropdownlist("A", dplENTERPRISE_UNIT);
            try
            {
                if (Request["mark"].ToString() != "")
                {
                    name = Request["mark"].ToString();
                    if (areaBll.getAreaName(name))
                    {
                        ArrayList list = new ArrayList();
                        list = areaBll.getAreaAll(name);
                        if ((string)list[4] == "")
                        {
                            dplENTERPRISE_PROV.SelectedValue = (string)list[2];
                            bindCity((string)list[2], (string)list[1]);
                            dplENTERPRISE_CITY.SelectedValue = (string)list[1];
                            string areaCode = (string)list[1];
                            if (areaBll.getIsArea(areaCode))
                            {
                                bindArea(areaCode,"");
                            }
                            else
                            {
                                ListItem item = new ListItem("请选择...", "");
                                dplENTERPRISE_AREA.Items.Insert(0, item);
                                dplENTERPRISE_AREA.SelectedIndex = 0;
                            }

                        }
                        else
                        {
                            dplENTERPRISE_PROV.SelectedValue = (string)list[2];
                            bindCity((string)list[2], (string)list[4]);
                            dplENTERPRISE_CITY.SelectedValue = (string)list[4];
                            string areaCode = (string)list[4];
                            if (areaBll.getIsArea(areaCode))
                            {
                                bindArea(areaCode,(string)list[1]);
                            }
                            dplENTERPRISE_AREA.SelectedValue = (string)list[1];
                        }
                  

                      

                    }
                    else
                    {
                        dplENTERPRISE_PROV.SelectedValue = areaBll.getSingleCode(name);
                        bindCity(dplENTERPRISE_PROV.SelectedValue, "");
                    }
                }
            }
            catch (Exception ex)
            {

            }

 

           
           

        }

    }

  
    private void bindDDL()
    {
        //省
        dplENTERPRISE_PROV.Items.Clear();
        ddlArea.Items.Clear();
        dplENTERPRISE_CITY.Items.Clear();

        AREABll abl = new AREABll();
        AreaData = abl.getProvince();
        dplENTERPRISE_PROV.DataValueField = "CODE";
        dplENTERPRISE_PROV.DataTextField = "CODE_NAME";
        dplENTERPRISE_PROV.DataSource = AreaData.Tables[0];
        dplENTERPRISE_PROV.DataBind();
        ListItem item = new ListItem("请选择...", "");
        dplENTERPRISE_PROV.Items.Insert(0, item);
        dplENTERPRISE_PROV.SelectedIndex = 0;

        //市

 

        dplENTERPRISE_CITY.Items.Clear();
        dplENTERPRISE_CITY.Items.Insert(0, item);
        dplENTERPRISE_CITY.SelectedIndex = 0;

        //全部
        DataSet ds = abl.getArea();
        ddlArea.DataValueField = "PARENT_AREA";
        ddlArea.DataTextField = "AREA";
        ddlArea.DataSource = ds.Tables[0];
        ddlArea.DataBind();

       

    }

    private void bindCity(string PARENT_AREA, string AREA_CODE)
    {
        dplENTERPRISE_CITY.Items.Clear();
        AREABll abl = new AREABll();
        AreaData = abl.getCity(PARENT_AREA);
        dplENTERPRISE_CITY.DataValueField = "AREA_CODE";
        dplENTERPRISE_CITY.DataTextField = "AREA_NAME";
        dplENTERPRISE_CITY.DataSource = AreaData.Tables[0];
        dplENTERPRISE_CITY.DataBind();
        if (AREA_CODE != null && AREA_CODE != "")
        {
            dplENTERPRISE_CITY.SelectedValue = AREA_CODE;
            this.Page.ClientScript.RegisterStartupScript(this.Page.GetType(), "addtxtvalue",
                "<script>document.getElementById('txtvalue').value = '" + AREA_CODE + "' </script>");
        }

        //全部区域
        DataSet ds = abl.getAllArea();
        dplAllArea.DataValueField = "PARENT_CODE";
        dplAllArea.DataTextField = "AREA";
        dplAllArea.DataSource = ds.Tables[0];
        dplAllArea.DataBind();
    }

    private void bindArea(string AREAC_CODE, string AREA_CODE  )
    {
        dplENTERPRISE_AREA.Items.Clear();
        AREABll areaBll = new AREABll();
        AreaData = areaBll.getArea(AREAC_CODE);
        dplENTERPRISE_AREA.DataValueField = "AREA_CODE";
        dplENTERPRISE_AREA.DataTextField = "AREA_NAME";
        dplENTERPRISE_AREA.DataSource = AreaData.Tables[0];
        dplENTERPRISE_AREA.DataBind();
        ListItem item = new ListItem("请选择...", "");
        dplENTERPRISE_AREA.Items.Insert(0, item);
        dplENTERPRISE_AREA.SelectedIndex = 0;

        if (AREA_CODE != null && AREA_CODE != "")
        {
            dplENTERPRISE_AREA.SelectedValue = AREA_CODE;
            this.Page.ClientScript.RegisterStartupScript(this.Page.GetType(), "addtxtArea",
                "<script>document.getElementById('txtArea').value = '" + AREA_CODE + "' </script>");
        }
   
    }
    protected void butCan_Click(object sender, EventArgs e)
    {
        this.Page.ClientScript.RegisterStartupScript(ClientScript.GetType(), "myscript", "<script>doback

();</script>");
    }

 

}

DropdownList绑定数据，JS获取
选择序号：
indexCity = document.getElementById('ctl00_ContentPlaceHolder2_txtENTERPRISE_CITY').selectedIndex;
选择CODE：
citys = document.getElementById('ctl00_ContentPlaceHolder2_txtENTERPRISE_CITY').value;
选择Name:
cityName = document.getElementById('ctl00_ContentPlaceHolder2_txtENTERPRISE_CITY').options[indexCity].text;