Powershell 无法理解此参数返回空值的原因

此PowerShell脚本运行SQL查询并填充Excel电子表格，然后通过电子邮件发送该电子表格：

$FileName = "C:\Users\user\Documents\Report.xlsx";
$ConnectionString = "OurConnectionString"
$secpasswd = "emailpassword"
$cred = New-Object System.Management.Automation.PSCredential ("emailaddress", $secpasswd)
$SmtpCred = $cred
$ToAddress = 'to@contoso.com'
$FromAddress = 'from@contoso.com'
$SmtpServer = 'smtp.server.com'
$SmtpPort = '587'
$Subject = 'Report'
$Body = "Here is your report"

$SqlQuery = @"
SELECT TOP 10 * FROM dbo.table
"@;

$SqlConnection = New-Object System.Data.SqlClient.SqlConnection;
$SqlConnection.ConnectionString = $ConnectionString;

$SqlCmd = New-Object System.Data.SqlClient.SqlCommand;
$SqlCmd.CommandText = $SqlQuery;
$SqlCmd.Connection = $SqlConnection;

$SqlAdapter = New-Object System.Data.SqlClient.SqlDataAdapter;
$SqlAdapter.SelectCommand = $SqlCmd;
$DataSet = New-Object System.Data.DataSet;
$SqlAdapter.Fill($DataSet);
$DataSetTable = $DataSet.Tables["Table"];

$xlsFile = @($DataSetTable | Export-Excel $FileName -AutoSize)

$SqlConnection.Close()

$Attachment = $xlsFile

$mailparam = @{
    To = $ToAddress
    From = $FromAddress
    Subject = $Subject
    Body = $Body
    Attachments = $Attachment
    SmtpServer = $SmtpServer
    Port = $SmtpPort
    Credential = $SmtpCred
}

Send-MailMessage @mailparam -UseSsl

运行此操作时出现的错误是：

Send-MailMessage : Cannot validate argument on parameter 'Attachments'. The argument is null, empty, or an element of the argument collection contains a null value. Supply a collection that does not contain any null values and then try the command again. At C:\Users\Desktop\Untitled1.ps1:58 char:18 + Send-MailMessage @mailparam -UseSsl + ~~~~~~~~~~ + CategoryInfo : InvalidData: (:) [Send-MailMessage], ParameterBindingValidationException + FullyQualifiedErrorId : ParameterArgumentValidationError,Microsoft.PowerShell.Commands.SendMailMessage 发送邮件消息：无法验证参数“附件”上的参数。这个 参数为null、空或参数集合的元素包含 空值。提供一个不包含任何空值的集合，然后 请重试该命令。 在C:\Users\Desktop\Untitled1.ps1:58 char:18 +发送MailMessage@mailparam-usesl + ~~~~~~~~~~ +CategoryInfo:InvalidData:（：）[Send MailMessage]，参数BindingValidationException +FullyQualifiedErrorId:ParameterArgumentValidationError，Microsoft.PowerShell.Commands.SendMailMessage

---

我搞不清楚

$Attachment

是如何以null或空结尾的？我知道我以前也写过类似的剧本，效果很好。我的脚本中是否遗漏了其他人可以看到的内容？此外，从技术上讲，我不需要先将Excel文件保存到文件系统中，我只需要将其作为附件发送电子邮件。因此，如果答案排除了保存到文件系统部分的操作（如果这是可以做到的话），那么就可以了。

参数

-Attachments

需要一个字符串或字符串列表

看

这应该是需要附加的文件的完整路径，因此需要先存储这些文件。一般来说，如果我以后不需要这些文件，你可以删除它们。还请注意，您需要传递

全名

由于我看不到

导出Excel

函数的输出，我假设它返回一个文件对象，那么这应该可以工作

$mailparam = @{
    To = $ToAddress
    From = $FromAddress
    Subject = $Subject
    Body = $Body
    Attachments = $xlsFile.FullName
    SmtpServer = $SmtpServer
    Port = $SmtpPort
    Credential = $SmtpCred
}

如果没有返回文件对象，则需要首先获取该项并传递“全名”

$MyExcelFile = Get-Item -Path 'C:\MyExcelFile.xlsx'

 $mailparam = @{
        To = $ToAddress
        From = $FromAddress
        Subject = $Subject
        Body = $Body
        Attachments = $MyExcelFile.FullName
        SmtpServer = $SmtpServer
        Port = $SmtpPort
        Credential = $SmtpCred
    }