我在更新面板中有几个按钮。我现在被要求用下拉列表替换按钮。我看到下拉列表上的 selectedindexchanged 事件比按钮单击事件慢得多。我有下面的代码。谁能指出我为什么会发生这种情况?或者我可以做些什么来使 selectedindexchanged 事件响应更快。
<asp:UpdatePanel ID="UpdatePanel" runat="server">
<ContentTemplate>
<div class="ui-widget-header" style="display: inline;">
<asp:Label ID="lblRefresh" runat="server" Text="Refresh Interval:" CssClass="label"
ForeColor="Black"></asp:Label>   
<asp:LinkButton ID="btnOFF" runat="server" OnClick="btnOFF_Click" Text="Off">
</asp:LinkButton> 
<asp:LinkButton ID="btn60SEC" runat="server" OnClick="btn60SEC_Click" Text="1Min">
</asp:LinkButton> 
<asp:LinkButton ID="btn5MIN" runat="server" OnClick="btn5MIN_Click" Text="5Min">
</asp:LinkButton> 
<asp:LinkButton ID="btn10MIN" runat="server" OnClick="btn10MIN_Click" Text="10Min">
</asp:LinkButton> 
<asp:LinkButton ID="btn15MIN" runat="server" OnClick="btn15MIN_Click" Text="15Min">
</asp:LinkButton>
<asp:DropDownList ID="ddlRefresh" runat="server" onselectedindexchanged="ddlRefresh_SelectedIndexChanged">
<asp:ListItem Text="OFF" Value="0"></asp:ListItem>
<asp:ListItem Text="5MIN" Value="5"></asp:ListItem>
<asp:ListItem Text="10MIN" Value="10"></asp:ListItem>
</asp:DropDownList>
</div>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ddlRefresh" EventName="SelectedIndexChanged"/>
</Triggers>
</asp:UpdatePanel>