如何用UpatePanel实现省市区的局部刷新-优快云博客

本文链接：https://blog.youkuaiyun.com/wangzhFy/article/details/5019846

本文探讨了ASP.NET中使用UpdatePanel进行局部刷新时遇到的问题，即首次点击下拉框不会触发局部刷新，之后的操作则正常刷新。文中提供了具体的代码片段以供参考。

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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>