与下拉列表相关的问题

问题描述

尊敬的先生，
我有3个下拉列表. 1st包含大陆.第二个包含国家.第三名包含城市.
我想首先选择一个大陆.当我选择大陆时，我需要在国家/地区下拉列表中选择国家/地区.当我选择一个国家/地区时，受人尊敬的城市将出现在城市下拉列表中.
我已经正确地做了所有这些.但是我的问题是，当我选择一个大陆时，页面会刷新，这需要很长时间.
请给我一些小例子的帮助.
先生，请同时提供带有ajax下拉菜单的解决方案.

谢谢.
Manoj joshi

Dear sir,
I have 3 dropdown lists. 1st contains the continental. 2nd contains country. 3rd contains city.
i want to choose first a continent. when i choose continent i need country in in country dropdown. and when i choose a country a respected city will came in city dropdown list.
i have done all of these correctly. but my problem is when i am selecting a continent my page goes to refresh and it''s taking a long time.
please provide me some help with the a little example.
sir please provide solution with ajax dropdown also.

thanking you.
Manoj joshi

推荐答案

<updatepanel id="UpdatePanel1" runat="server">
<contenttemplate>

</contenttemplate>
</updatepanel>

<asp:DropDownList ID="continental" runat="server" OnSelectedIndexChanged="taha"></asp:DropDownList>

        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <asp:DropDownList ID="country" runat="server"></asp:DropDownList>
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger  ControlID="continental"                 EventName="taha"/>
            </Triggers>
        </asp:UpdatePanel>

只需将要更新的内容放在ContentTemplate中的回调中即可.
并将触发器的controlID设置为导致回发事件的控件ID！

just put the content that update in call back in ContentTemplate.
and set the controlID of your trigger to ID of control that causes the postback event!

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