请教一个用CommonDialog把DataGrid中的数据导出成excel文件的问题

请教一个用CommonDialog把DataGrid中的数据导出成excel文件的问题:
我用的是以下的代码:
Dim strFileName As String
Dim time As String
Dim objFileSystem As Object
Dim objExcelText As Object
Dim strTableString As String, i As Integer
Dim rs_excel As New ADODB.Recordset
Dim strConn As String
Dim sql As String
Dim strTableString2 As String

time = Format(DateTime.Now, "yyyy-mm-dd")
sql = "select * from 订单表 where 日期=#" & time & "#"
rs_excel.CursorLocation = adUseClient
rs_excel.Open sql, conn, adOpenKeyset, adLockPessimistic
For i = 0 To rs_excel.Fields.Count - 1
strTableString = strTableString & rs_excel.Fields(i).Name & Chr(9) '獲取字段名
Next
strTableString2 = strTableString

strTableString = rs_excel.GetString '字段名+數據庫的記錄
CommonDialog2.CancelError = False
CommonDialog2.FileName = time & "系统导出数据" '默認生成的文件名
CommonDialog2.DialogTitle = "保存导出文件"
CommonDialog2.Filter = "Excel文件(*.xls)|*.xls|HTML文档(*.html)|*.htm"
CommonDialog2.DefaultExt = ".xls"
CommonDialog2.Flags = cdlOFNOverwritePrompt
CommonDialog2.ShowSave
strFileName = CommonDialog2.FileName

Set objFileSystem = CreateObject("Scripting.FileSystemObject")
Set objExcelText = objFileSystem.createtextfile(CommonDialog2.FileName, True)
objExcelText.writeline (strTableString2)
objExcelText.writeline (strTableString)
objExcelText.Close

数据是可以导出成.XLS文件,但是当我直接在access中用 "获取外部数据" 选项想把导出生成的.xls文件导入到其中的一个表时,却提示说:此文件格式不对.
各位高手,能不能告诉我问题出在哪里,如何改动????