服务器升级至2022后PowerShell脚本运行异常求助

我有一段脚本曾在Windows Server 2012 R2连接代理上稳定运行，将连接代理升级至2022后，脚本运行异常：虽能发送邮件，但邮件内容为空。手动运行脚本时出现如下错误：

You cannot call a method on a null-valued expression.
At C:\PS-Scripts\rdstats.ps1:28 char:5

• $ob = [PSCustomObject]@{
  

• ~~~~~~~~~~~~~~~~~~~~~~~~
  

  • CategoryInfo : InvalidOperation: (:) [], RuntimeException
  • FullyQualifiedErrorId : InvokeMethodOnNull

我推测是$ob = [PSCustomObject]@{部分被判定为空，但将以下循环代码单独在PowerShell窗口运行时无报错：

foreach ( $rdhost in $rdhosts )
{
    $rdp = Test-NetConnection -ComputerName $rdhost.SessionHost -Port 3389

    $ob = [PSCustomObject]@{
        CollectionName      = $rdhost.CollectionName
        SessionHost         = $rdhost.SessionHost
        InCluster           = $rdhost.NewConnectionAllowed
        RemotePort          = $rdp.RemotePort
        PortAlive           = $rdp.TcpTestSucceeded
        PingSucceeded       = $rdp.PingSucceeded
        PingReplyDetails    = $rdp.PingReplyDetails.RoundtripTime.ToString() + " ms"
        }

    $objs += $ob
}

另外，在2012R2机器上针对2022连接代理运行该脚本可成功，因此问题可能并非出在连接代理，而是2012R2与2022的PowerShell版本差异（4.0 vs 5.1）。请问为何PowerShell 5.1会判定$ob = [PSCustomObject]@{为空？以下是完整脚本：

###BEGIN TODO CONFIG EMAIL

#$Username = 'user@domain.com'
#$Password = ''
$emailTo = "user@domain.com"
$bccTo = "dg@domain.com"
$emailFrom = "status@domain.com"

###END TODO CONFIG EMAIL

#$pass = ConvertTo-SecureString -AsPlainText $Password -Force

# Users you password securly
#$MySecureCreds = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList $Username,$pass 



Import-Module RemoteDesktop
$rdhosts = Get-RDSessionHost -CollectionName "RD Collection 1"

$objs = @()

foreach ( $rdhost in $rdhosts )
{
    $rdp = Test-NetConnection -ComputerName $rdhost.SessionHost -Port 3389

    $ob = [PSCustomObject]@{
        CollectionName      = $rdhost.CollectionName
        SessionHost         = $rdhost.SessionHost
        InCluster           = $rdhost.NewConnectionAllowed
        RemotePort          = $rdp.RemotePort
        PortAlive           = $rdp.TcpTestSucceeded
        PingSucceeded       = $rdp.PingSucceeded
        PingReplyDetails    = $rdp.PingReplyDetails.RoundtripTime.ToString() + " ms"
        }

    $objs += $ob
}

$str = Out-String -InputObject $objs -Width 100

Send-MailMessage -From $emailFrom -To $emailTo -BCC $bccTo -Subject "RD Collection TS Audit" -Body $str -SmtpServer mail.domain.com -Port 25

错误提示的InvokeMethodOnNull并非是[PSCustomObject]@{...}本身为空，而是构建对象时，某属性调用了空值的方法。具体问题出在$rdp.PingReplyDetails.RoundtripTime.ToString()这一行：

• PowerShell 4.0（Windows Server 2012 R2）中，即使Ping失败，$rdp.PingReplyDetails会返回默认对象（比如RoundtripTime为0），不会为null；
• PowerShell 5.1（Windows Server 2022）中，Ping失败时$rdp.PingReplyDetails直接为null，此时调用.RoundtripTime就会触发空值调用错误，导致$ob对象创建失败，最终$objs数组为空，邮件内容无数据。

单独运行循环时无报错，大概率是测试环境中所有主机都能Ping通，$rdp.PingReplyDetails不为null，未触发问题。

解决步骤 #

1. 添加空值判断：在访问$rdp.PingReplyDetails.RoundtripTime前先检查是否为null，避免空对象调用：

PingReplyDetails    = if ($rdp.PingReplyDetails) { $rdp.PingReplyDetails.RoundtripTime.ToString() + " ms" } else { "Ping Failed" }

2. 优化数组构建：PowerShell中+=扩展数组效率低，建议直接将循环输出的对象赋值给变量：

$objs = foreach ( $rdhost in $rdhosts )
{
    $rdp = Test-NetConnection -ComputerName $rdhost.SessionHost -Port 3389

    [PSCustomObject]@{
        CollectionName      = $rdhost.CollectionName
        SessionHost         = $rdhost.SessionHost
        InCluster           = $rdhost.NewConnectionAllowed
        RemotePort          = $rdp.RemotePort
        PortAlive           = $rdp.TcpTestSucceeded
        PingSucceeded       = $rdp.PingSucceeded
        PingReplyDetails    = if ($rdp.PingReplyDetails) { $rdp.PingReplyDetails.RoundtripTime.ToString() + " ms" } else { "Ping Failed" }
    }
}

3. 验证运行：修改后重新执行脚本，即使有主机Ping失败，也能正常生成PSCustomObject，$objs不会为空，邮件内容可正常展示。

内容的提问来源于stack exchange，提问作者SubnetMask