Dropdown SelectedIndexChanged事件未触发

问题描述

我的页面上有下拉列表，其中包含必填字段验证器.如果我从该下拉列表中选择一项，则会触发selectedindexchanged事件.如果我不会从该下拉菜单中选择任何内容，则将显示requiredfieldvalidator的消息.现在，
如果我选择一个项目，则selectedindexchanged事件不会触发.以下是我的代码.

Hi,

I have dropdown in my page which is having requiredfield validator. If I select an item from that dropdown selectedindexchanged event is firing. If i wont select anything from that dropdown message from requiredfieldvalidator will be shown. Now,
If I select an item selectedindexchanged event is not firing. Below is my code.

<asp:DropDownList ID="ddlCampuses"; runat="server"; OnSelectedIndexChanged="ddlCampuses_SelectedIndexChanged"; AutoPostBack="True" AppendDataBoundItems="True">/asp:DropDownList>

推荐答案

<asp:DropDownList ID="ddlCampuses" runat="server" OnSelectedIndexChanged="ddlCampuses_SelectedIndexChanged" AutoPostBack="True" AppendDataBoundItems="True">
<asp:ListItem Value="-1" Selected="True">Select</asp:ListItem>
</asp:DropDownList>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ErrorMessage="* required" ControlToValidate="ddlCampuses" InitialValue="-1"></asp:RequiredFieldValidator>

希望对您有所帮助.

Hope this will help.

<asp:UpdatePanel ID="upDivision" runat="server">
 <ContentTemplate>

place your dropeDown With requiredfield validator.

</ContentTemplate>

 <Triggers>
 <asp:AsyncPostBackTrigger ControlID="Your DropDown ID" EventName="SelectedIndexChanged" />

   </asp:UpdatePanel>

希望对您有帮助...

i hope it will help you...

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