如下设置控件属性：

<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional" ChildrenAsTriggers="true">
	<ContentTemplate>
		<div>
			<asp:FileUpload ID="dcFile" runat="server" />
			<asp:Button ID="btnImport" runat="server" Text="导入" OnClick="btnOperate_Click">
			</asp:Button>
			<asp:Button ID="btnRemove" runat="server" Text="删除" OnClick="btnOperate_Click" OnClientClick="return confirm('确定要删除吗？')" >
			</asp:Button>
		</div>
	</ContentTemplate>
	<Triggers>
		<asp:PostBackTrigger ControlID="btnImport" />
		<asp:PostBackTrigger  ControlID="btnRemove" />
	</Triggers>
</asp:UpdatePanel>