用于发送批量电子邮件的PowerShell脚本

Question

I have written a script below that reads the email ID from the XML file. Loads the email ID filtered using group ID and then send emails to all the email IDs on that ArrayList. I don't know what is the problem below, I am not getting any emails.

function Test {
   function Send-Mail {
        Param($smtp, $from, $to, $subject, $body)
        $smtp = New-Object System.Net.Mail.SmtpClient($smtp)
        $mail = New-Object System.Net.Mail.MailMessage
        $mail.From = $from
        $mail.To.Add($to)
        $mail.Subject = "subject goes here"
        $mail.Body = "This is test"
        $smtp.Send($mail)
    }
    #Read the xml file and typecast it to System.Xml.XmlDocument
    [Xml]$XmlData = Get-Content Email.xml
    $ArrayEmail = New-Object System.Collections.ArrayList
    $subject = "Testing PowerShell email"
    $from = "a@134.com"
    $smtp = "test.test123.com"
    $body = "The body goes here"
    #get the email list from group id
    $ArrayEmail = $XmlData.emaillist.group |
                  Where-Object {$_.id -eq "IT"} |
                  Select-Object emailid
    $to = New-Object System.Collections.ArrayList
    #store the email ids in array
    for ($i = 0; $i -lt $ArrayEmail.emailid.Count; $i++) {
        $to.Add($ArrayEmail.emailid[$i])
    }
    Send-Mail -Smtp $smtp -From $from -To $to[$i] -Subject $subject -Body $body
 }

Here is my sample XML file:

<emaillist>
  <group id="IT">
    <emailid>a@123.com</emailid>
    <emailid>b@345.com</emailid>
  </group>
  <group id="Admin">
    <emailid>admin@admin.com</emailid>
  </group>
</emaillist>

Not sure what I have done wrong or missed anything as everything seems to be alright. But I still don't get any emails. My smtp is all good, the sender and receivers emails are all good as well.

Answer 1

What you have there is called off-by-one error . After your for loop completes the value of the loop variable $i is the highest index of $to plus one . Hence $to[$i] evaluates to $null , because you're trying to access the element after the last element in the ArrayList (which doesn't exist), and PowerShell returns $null for things like that instead of throwing an error.

Replace this:

$ArrayEmail = $XmlData.emaillist.group |
              Where-Object {$_.id -eq "IT"} |
              Select-Object emailid
$to = New-Object System.Collections.ArrayList
#store the email ids in array
for ($i = 0; $i -lt $ArrayEmail.emailid.Count; $i++) {
    $to.Add($ArrayEmail.emailid[$i])
}
Send-Mail -Smtp $smtp -From $from -To $to[$i] -Subject $subject -Body $body

with this:

$to = $XmlData.emaillist.group |
      Where-Object {$_.id -eq "IT"} |
      Select-Object -Expand emailid
Send-Mail -Smtp $smtp -From $from -To $to -Subject $subject -Body $body

and the problem will disappear.

---

To have the mail sent to all recepients you need to add them one by one:

function Send-Mail {
    Param($smtp, $from, $to, $subject, $body)
    $smtp = New-Object System.Net.Mail.SmtpClient($smtp)
    $mail = New-Object System.Net.Mail.MailMessage
    $mail.From = $from
    
    $mail.Subject = "subject goes here"
    $mail.Body = "This is test"
    $smtp.Send($mail)
}

However, rather than re-invent the wheel you should use the Send-MailMessage cmdlet, as others have already suggested:

Send-MailMessage -SmtpServer $smtp -From $from -To $to -Subject $subject -Body $body