我有以下代码，它工作得很好，只是它不能正确地关闭Excel。它使一个Excel进程处于运行状态。
有没有一种方法可以在不终止进程的情况下正确关闭Excel？
由于我在运行此脚本时正在使用其他Excel文件，因此无法终止所有活动的Excel进程。
我想我在网上找到的都试过了。

$WorkDir = "D:\Test\QR_ES\RG_Temp"
$BGDir = "D:\Test\QR_ES\3_BG"
$File = "D:\Test\QR_ES\4_Adr_Excel\KD_eMail.xlsx"
$SentDir = "D:\Test\QR_ES\RG_Temp\Sent\Dunning"

chdir $WorkDir

$firstPageList = Get-ChildItem "$WorkDir\1*.pdf" -File -Name

ForEach ($firstPage in $firstPageList)
{
$secondPage = "$BGDir\BG_RG.pdf"

$output = "Dunn-$firstPage"

invoke-command {pdftk $firstPage background $secondPage output $output}}

del 1*.pdf

gci $WorkDir\Dunn-*.pdf | rename-item -newname {$_.Name.Substring(5)} -Force

$Excel = New-Object -ComObject Excel.Application
$Excel.visible = $false
$Workbook = $Excel.workbooks.open($file)

$DunnList = Get-ChildItem "$WorkDir\1*.pdf" -File -Name

ForEach ($Dunn in $DunnList)
{
$Worksheets = $Workbooks.worksheets
$Worksheet = $Workbook.Worksheets.Item("KD_eMail")
$Range = $Worksheet.Range("A1").EntireColumn
$DunnSearch = $Dunn.Substring(0,5)
$SearchString = $DunnSearch
$Search = $Range.find($SearchString)
$Recipient = $Worksheet.Cells.Item($Search.Row, $Search.Column + 1)

$Msg = "<span style='font-family:Calibri;font-size:12pt;'>Test</span>"

$Outlook = New-Object -ComObject Outlook.Application
$namespace = $Outlook.GetNameSpace("MAPI")
$namespace.Logon($null, $null, $false, $true)
$EmailFrom = ('test@test.com')
$account = $outlook.Session.Accounts.Item($EmailFrom)
$Mail = $Outlook.CreateItem(0)
$Mail.HTMLBody = $Msg
$Mail.Subject = "OP - $SearchString"

$Mail.To = $Recipient

function Invoke-SetProperty {
    param(
        [__ComObject] $Object,
        [String] $Property,
        $Value        
    )
    [Void] $Object.GetType().InvokeMember($Property,"SetProperty",$NULL,$Object,$Value)
   }
Invoke-SetProperty -Object $mail -Property "SendUsingAccount" -Value $account

$Mail.Attachments.Add("$WorkDir\$Dunn")
$Mail.Save()
$Mail.close(1)
$Mail.Send()}}

$workbook.close($false)

$Excel.Quit()

chdir $WorkDir

del 1*.pdf