powershell - 使用可能指定或未指定的参数运行内置 cmdlet

Question

我的脚本中有一个函数，它封装了 send-mailmessage cmdlet，并在发送每封电子邮件之前执行了一些逻辑。

我的问题是如何创建参数列表以输入发送邮件消息，以便抄送、密送和附件是可选的。

我之前所做的只是一些 if 语句。但是将 -Cc 添加到混合中，这将是 9 个 if 语句而不是当前的 4 个。我想我想太多了，必须有一个更简单的方法。

精简功能:

Function Send-Email ($To, $Cc, $Bcc, $Subject, $From, $Body, $Attachments)
{
    #Some more code goes here that sometimes modifies the incoming parameters
    $EmailServer = my.mail.server
    Try
    {
        #Need to add ability for $Cc to be optional
        if ($Attachments -and $Bcc) {send-mailmessage -to $To -Cc $Cc -Bcc $Bcc -subject $Subject -From $From -body $Body -smtpserver $EmailServer -attachments $Attachments -ErrorAction "Stop"}
        if ($Attachments -and -not $Bcc) {send-mailmessage -to $To -Cc $Cc -subject $Subject -From $From -body $Body -smtpserver $EmailServer -attachments $Attachments -ErrorAction "Stop"}
        if ($Bcc -and -not $Attachments) {send-mailmessage -to $To -Cc $Cc -Bcc $Bcc -subject $Subject -From $From -body $Body -smtpserver $EmailServer -ErrorAction "Stop"}
        if (-not $Attachments -and -not $Bcc) {send-mailmessage -to $To -Cc $Cc -subject $Subject -From $From -body $Body -smtpserver $EmailServer -ErrorAction "Stop"}
    }
    Catch [system.exception]
    {
        "Failed to send email to $($To) due to: $_"  #Logging removed for SO example code
    }
    Finally
    {}
}

我尝试将参数生成为一个长字符串或字符串数​​组，然后使用调用表达式。我也尝试过，但使用“&”符号来执行 cmdlet。

当我尝试时，shell 会提示我输入参数。

PS E:\script> invoke-expression 'send-mailmessage $a'

cmdlet Send-MailMessage at command pipeline position 1
Supply values for the following parameters:
From: 


PS E:\script> & send-mailmessage $a

cmdlet Send-MailMessage at command pipeline position 1
Supply values for the following parameters:
From: 

我尝试将 $Cc 设置为 $Null、$False 或空字符串“”，但 send-mailmessage 提示参数无效。

我觉得我在这里遗漏了一些简单的东西，但在我看来，这个函数应该看起来像这个无效的例子:

Function Send-Email ($To, $Cc, $Bcc, $Subject, $From, $Body, $Attachments)
{
    #Some more code goes here that sometimes modifies the incoming parameters
    $EmailServer = my.mail.server
    if ($Cc) {$CcArg = "-Cc $Cc"}
    if ($Bcc) {$BccArg = "-Bcc $Bcc"}
    if ($Attachments) {$AttachArg = "-Attachments $Attachments"}
    Try
    {
        send-mailmessage -to $To ($CcArg) ($BccArg) -subject $Subject -From $From -body $Body -smtpserver $EmailServer $AttachArg -ErrorAction "Stop"
    }
    Catch [system.exception]
    {
        "Failed to send email to $($To) due to: $_"  #Logging removed for SO example code
    }
    Finally
    {}
}

感谢您的任何想法或建议。

Answer 1

啊哈哈!
找到这篇文章:Inline expansion of powershell variable as cmdlet parameter?

所以函数看起来像(未完全测试，但原理有效):

Function Send-Email ($To, $Cc, $Bcc, $Subject, $From, $Body, $Attachments)
{
    #Some more code goes here that sometimes modifies the incoming parameters
    $EmailServer = my.mail.server
    $MoreArgs = @{}
    if ($Cc) {$MoreArgs.Add("Cc",$Cc)}
    if ($Bcc) {$MoreArgs.Add("Bcc",$Bcc)}
    if ($Attachments) {$MoreArgs.Add("Attachments",$Attachments)}
    Try
    {
        send-mailmessage -to $To -subject $Subject -From $From -body $Body -smtpserver $EmailServer -ErrorAction "Stop" @MoreArgs
    }
    Catch [system.exception]
    {
        "Failed to send email to $($To) due to: $_"  #Logging removed for SO example code
    }
    Finally
    {}
}