PowerShell对值和数组的作用不同?

我试图使用PowerShell从Active Directory中获取一些信息,但我得到了一些奇怪的行为。这是我的剧本:

$toFind = ( 'bobjones', 'samsmith' )

filter Get-AdUser {
    $strFilter = "(&(objectCategory=User)(sAMAccountName=$_))"

    $objDomain = New-Object System.DirectoryServices.DirectoryEntry
    $objSearcher = New-Object System.DirectoryServices.DirectorySearcher
    $objSearcher.SearchRoot = $objDomain
    $objSearcher.PageSize = 1000
    $objSearcher.Filter = $strFilter

    $colProplist = ("name", "department")
    foreach ($i in $colPropList){$objSearcher.PropertiesToLoad.Add($i)}

    ($objSearcher.FindAll() | %{$_.Properties})
}

"paul" | get-aduser # Works
$toFind | get-aduser # Doesn't work?!

前者打印出我所期望的,一个属性表;后者最终只是重复打印“0 1”,尽管我不知道为什么。为什么单例工作而不是数组?