下面这段代码，没有导出excel，为啥？

\'
Dim path As String = _PathAttachment & "\\Documents\\分层审核\\"
Dim r As Row = _ftb.Current
Dim ex As New Exporter
ex.SourceTableName = e.Form.TableName \'指定导出表
ex.FilePath = path & "eLPA_" & Format(Date.Today, "yyyymmdd") & "_" & _UserName & ".xlsx" \'指定目标文件
ex.Format = "Excel" \'导出格式为Excel
ex.Fields = "跟踪号,审核单号,问题编号,审核员,审核日期,审核区域,审核对象,审核发现,是否重复,发生次数,任务次数,处置" \'指定导出字段
ex.Filter = "审核员 =\'" & _UserName & "\'"
ex.Export() \'开始导出