请查看以下点击事件...
Protected Sub btnDownloadEmpl_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnDownloadEmpl.Click '下载员工数据表 Dim emplTable As DataTable = SiteAccess.DownloadEmployee_H() '获取当前日期并格式化 Dim d As String = Format(Date.Now, "d") '将日期转换为数组 Dim ad() As String = d.Split("/") '拼接文件名 Dim fd As String = ad(0) & ad(1) Dim fn As String = "E_" & fd & ".csv" '设置响应类型和文件名 Response.ContentType = "text/csv" Response.AddHeader("Content-Disposition", "attachment; filename=" & fn) '创建CSV文件并输出到响应流 CreateCSVFile(emplTable, Response.Output) '刷新响应流并结束响应 Response.Flush() Response.End() '在页面上显示标签 lblEmpl.Visible = True End Sub这段代码简单地将数据从datatable导出到csv文件。问题在于lblEmpl.Visible=true永远不会被执行,因为这段代码不会导致向服务器发送请求。即使我把代码行lblEmpl.Visible=true放在click事件的顶部,该行也能够正常执行,但页面仍然没有更新。我该如何解决这个问题?