如何用UpatePanel实现省市区的局部刷新

来源：互联网发布：听英语单词的软件编辑：程序博客网时间：2024/06/07 19:40

代码如下：

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
                                                                <ContentTemplate>
                                                                <asp:DropDownList ID="ddlProvince" runat="server" AutoPostBack="True"
                                                                        onselectedindexchanged="ddlProvince_SelectedIndexChanged">
                                                                       </asp:DropDownList>
                                                                <asp:DropDownList ID="ddlCity" runat="server" AutoPostBack="True"
                                                                        onselectedindexchanged="ddlCity_SelectedIndexChanged">

                                                                </asp:DropDownList>
                                                                <asp:DropDownList ID="ddlCounty" runat="server">

                                                                </asp:DropDownList>

                                                               </ContentTemplate>
                                                           <Triggers>
                                                                    <asp:AsyncPostBackTrigger ControlID="ddlProvince"
                                                                        EventName="SelectedIndexChanged" />
                                                                    <asp:AsyncPostBackTrigger ControlID="ddlCity"
                                                                        EventName="SelectedIndexChanged" />
                                                                </Triggers>

</asp:UpdatePanel>

但是第一次点下拉框时，不会局部刷新，以后就可以，不知道什么原因,请高手指点