PowerShell - Show Property of Parent Object and Child Object - powershell

Question

If I have a list of email metadata in a hashtable and each email has a hashtable with a list of attachments inside that object, like this:
$Emails = #{
ID = "E123";
Subject = "Check this out";
Attachments = #{
ID = "A123";
Name = "FunnyPic.jpg"
}
}
And then that hashtable is converted to a PSObject like this:
$EmailsObject = New-Object -TypeName PSObject -Property $Emails
And I want to do something like this:
$EmailsObject | Select ID, Attachments.ID
How would I do that?
I want to associate the ID of the Email with the ID's of the associated attachments.

Answer 1

You will want to use calulated properties.
$Emails | Select-Object -Property #{Name='ID';Expression={$_.ID};},#{Name='AttachmentId';Expression={$_.Attachments.ID};}
You can shorten Name and Expression to n and e.
See this article for more.

Answer 2

you need to use a calculated property if you use Select-Object. something like this ...
$Emails = #{
ID = "E123";
Subject = "Check this out";
Attachments = #{
ID = "A123";
Name = "FunnyPic.jpg"
}
}
$EmailsObject = New-Object -TypeName PSObject -Property $Emails
$EmailsObject |
Select-Object ID,
#{
n = 'AttID'
e = {$_.Attachments.ID}
}
output ...
ID AttID
-- -----
E123 A123