<asp:ScriptManager ID="ScriptManager1" runat="server">/asp:ScriptManager>

<asp:UpdatePanel ID="UpdatePanel1" runat="server"><ContentTemplate><p><span class="redcolor">* </span>选择地区：<asp:DropDownList ID="ProvinceSelect" AutoPostBack="True"  runat="server" OnSelectedIndexChanged="GetCityName_onClick"></asp:DropDownList><asp:DropDownList runat="server" ID="CitySelect" AutoPostBack="True" OnSelectedIndexChanged="Getcounty_OnClick"  ></asp:DropDownList><asp:DropDownList   AutoPostBack="True" runat="server" ID="County"></asp:DropDownList></p></ContentTemplate><Triggers><asp:AsyncPostBackTrigger ControlID="ProvinceSelect" EventName="SelectedIndexChanged" /></Triggers></asp:UpdatePanel>

protected void Page_Load(object sender, EventArgs e){if (!IsPostBack){ProvinceSelect.DataSource = BFL.GetPrivoces();ProvinceSelect.DataTextField = "RegionName";ProvinceSelect.DataValueField = "RegionId";ProvinceSelect.DataBind();ProvinceSelect.Items.Insert(0, new ListItem("请选择", string.Empty)); CitySelect.Items.Insert(0, new ListItem("请选择", string.Empty)); County.Items.Insert(0, new ListItem("请选择", string.Empty)); } }

        #region 省市县数据绑定//市级绑定public void GetCityName_onClick(object sender, EventArgs e){CitySelect.DataSource = BFL.GetCitys(int.Parse(ProvinceSelect.SelectedItem.Value));CitySelect.DataTextField = "RegionName";CitySelect.DataValueField = "RegionId";CitySelect.DataBind();County.Items.Insert(0, new ListItem("请选择", string.Empty));}//县级绑定public void Getcounty_OnClick(object sender, EventArgs e){County.DataSource = BFL.GetCitys(int.Parse(CitySelect.SelectedItem.Value));County.DataTextField = "RegionName";County.DataValueField = "RegionId";County.DataBind();County.Items.Insert(0,new ListItem("请选择",string.Empty));}#endregion