为什么我的 if 语句没有被正确阅读？

Question

我有一个脚本可以从本地或远程计算机备份用户配置文件并将其放置到共享中：$Global:Shared_BackupPath = "\\server\share\"。我已经对其进行了更多的调整，最后只是将一些变量变成了 全局 变量（不确定这是否是问题 - 不明白为什么会这样）。

这是条件：

if(-not (Get-EventSubscriber)){

我尝试将其更改为 -eq $null 以查看是否有任何不同，但没有。

它只是没有正确分析条件并在所有作业完成之前继续显示我的消息框：它是“应该”等到没有更多事件然后显示消息框：

        Register-ObjectEvent -InputObject $job -EventName StateChanged -Action {
        #Start-Sleep -Milliseconds 500
            $eventSubscriber | Unregister-Event
            $eventSubscriber.Action | Remove-Job
            if(-not (Get-EventSubscriber)){
                $Profile_Sum = Get-ChildItem -Path $Global:BackUp_Path -Recurse |
                    Measure-Object -Property length -Sum |
                    Select-Object -ExpandProperty Sum
                        $Size = try{if($Profile_Sum -lt 1048576){ $TinyByte = "  {0:N2}" -f ($Profile_Sum / 1KB) + " KB"; $TinyByte }
                        elseif($Profile_Sum -gt 1048576 -and $Profile_Sum -lt 1073741824){ $MediumByte = "  {0:N2}" -f ($Profile_Sum / 1MB) + " MB"; $MediumByte }
                        elseif($Profile_Sum -gt 1073741824){ $GiganticByte = "  {0:N2}" -f ($Profile_Sum / 1GB) + " GB"; $GiganticByte } } Catch {}
            
                $Begin_Time = Get-Item -Path $Global:BackUp_Path | Select-Object -ExpandProperty LastWriteTime
               
                $End_Time = Get-Date -Format G  

                Get-Job | Remove-Job 
                [System.Windows.MessageBox]::Show("Copying Complete!`nStart Time: $Begin_Time  `nEnd Time: $End_Time `nProfile Size copied: $Size")
                       
                        }
                    } | Out-Null 
                }

由于活动本身被注册为工作，我觉得我可能有一个想法，但不太确定如何去做，并让它等到完成 所有 个工作后再显示复制完成时通知我的消息框。除此之外，该脚本运行良好，任何阅读此内容的人都可以随意使用它。这是完整的脚本：

Function PFL-UserBackUp{
[cmdletbinding()]
    Param(
        [Parameter(Mandatory=$false,
                   ValueFromPipeLine=$true,
                   ValueFromPipeLineByPropertyName=$true)]
        [Alias('CN','Computer','server','node')]
        [ValidateLength(1, 15)]
        [String[]]$ComputerName = $env:COMPUTERNAME )
Begin{
    $Global:Shared_BackupPath = "\\server\share\"
    }
Process{
    Foreach($Computer in $ComputerName){
        Try{
            $PSSession  = New-PSSession -ComputerName $Computer -ErrorAction Stop 

            [array]$User_List = Invoke-Command -ScriptBlock { 
                                    Get-ChildItem -Path "C:\Users" -Exclude Public, Default* | 
                                    Sort-Object -Property LastWriteTime -Descending } -Session $PSSession

    $userinfo1 = foreach ($user in $User_List.name) {
      $userinfo = (net user $user /domain | Select-String "Full Name" -ErrorAction SilentlyContinue) -replace "Full Name                    ", "" 2>&1 | Out-String -Stream
        if ($userinfo.Length -lt 4) { "NO DISPLAY NAME in ADUC" }
            elseif($LASTEXITCODE -eq 2) { "ACCOUNT NOT in ADUC" }
            elseif($LASTEXITCODE -eq 0) { $userinfo }
                else { "Error occured" }
                }
 
     $(for($i=0; $i -lt $User_List.Count; $i++){
        [pscustomobject]@{
                'User Display Name    '  = "$($i): $($userinfo1[$i])"
                '    NAME    '           = $User_List.name[$i]
                'Last Modified'          = "$($User_List.LastWriteTime[$i])" 
                'Profile Size '          = Try{
                                             $ProfilePath = $User_List.FullName[$i] 
                                             $Profile_Sum = Invoke-Command -ScriptBlock {
                                                        Get-ChildItem -Path $Using:ProfilePath -Recurse |
                                                                Where-Object {$_.PSParentPath -match "Documents|Desktop|Music|Videos|Downloads|Links|Pictures|Favorites|Contacts" -and $_.DirectoryName -notmatch "OneDrive" } | 
                                                                Measure-Object -Property length -Sum |
                                                                Select-Object -ExpandProperty Sum } -Session $PSSession
                                                                    if($Profile_Sum -lt 1048576){ $TinyByte = "  {0:N2}" -f ($Profile_Sum / 1KB) + " KB"; $TinyByte }
                                                                    elseif($Profile_Sum -gt 1048576 -and $Profile_Sum -lt 1073741824){ $MediumByte = "  {0:N2}" -f ($Profile_Sum / 1MB) + " MB"; $MediumByte }
                                                                    elseif($Profile_Sum -gt 1073741824){ $GiganticByte = "  {0:N2}" -f ($Profile_Sum / 1GB) + " GB"; $GiganticByte } #Profile Size
                                              } Catch { "$($Error[0].Exception.Message.Split('.')[2].Trim())!" }
                                         }
                                    } ) | Out-Host

Write-Host "Press 'Q' to quit."
$ii = Read-Host -Prompt "Enter Number of Profile to Back-Up"
$i  = $ii.Trim() -split ","
    if([String]::IsNullOrEmpty($i) -eq $true) { "Null string"; Break }
    elseif($i.ToLower() -like "q*") {"Q was selected. Stopping script."; Break }


<#    
    " "    
    "     Following Profiles will be Saved:"
    "     ------------------------------------"
        foreach($i in $index) { "$($i.trim()): $($userinfo1[$i])" }
    " "


$Confirm = Read-Host -Prompt "Are you sure you want to continue? [Y/N]"
    if($Confirm.ToLower().TrimStart() -like "n*" -or $Confirm.ToLower() -like "q*"){Break} 
    if([String]::IsNullOrEmpty($Confirm.Trim()) -eq $true) { "Null string"; Break }#>


        $Profile_Path       = "C:\Users\$($User_List.name[$i])"
        $Literal_Name       = $userinfo1[$i].Replace('/','-')
        $Global:BackUp_Path = "$Global:Shared_BackupPath$Literal_Name"
        $Test_Path          = Test-Path -Path $Global:BackUp_Path 
            if($Test_Path -eq $false){
                New-Item -Path $Global:BackUp_Path -ItemType Directory | Out-Null
                Start-Process $Global:BackUp_Path}
            elseif($Test_Path -eq $true){
                $Find_OldName  = Get-ChildItem -Path "$Global:Shared_BackupPath" -Filter "$Literal_Name" -Directory |
                                     Sort-Object -Property LastWriteTime -Descending |
                                     Select-Object -ExpandProperty BaseName -First 1

                 $New_PathName = $Find_OldName + "1"
                    New-Item -Path "$Global:Shared_BackupPath" -Name $New_PathName -ItemType Directory -OutVariable Global:BackUp_Path | Out-Null #Global:BackUp_Path variable declared
                    $Global:BackUp_Path = $Global:BackUp_Path.FullName
                    Start-Process $Global:BackUp_Path}


$Global:Start_Time = Get-Date -Format G


#Favorites Copy   
$FireFox_Favorites = "C:\Users\$($User_List.name[$i])\AppData\Roaming\Mozilla\Firefox\Profiles\*.default\places.sqlite"
$Chrome_Favorites  = "C:\Users\$($User_List.name[$i])\AppData\Local\Google\Chrome\User Data\Default\Bookmarks"
$Chrome_Favorites2 = "C:\Users\$($User_List.name[$i])\AppData\Local\Google\Chrome\User Data\Default\Bookmarks.bak"
$Sticky_Notes      = "C:\Users\$($User_List.name[$i])\AppData\Local\Packages\Microsoft.MicrosoftStickyNotes_8wekyb3d8bbwe\LocalState\plum.sqlite"

$Favorites_Array   = @($FireFox_Favorites,$Chrome_Favorites,$Chrome_Favorites2,$Sticky_Notes)
    Foreach($File in $Favorites_Array){
        $Test_File = Invoke-Command -ScriptBlock { Test-Path -Path $File }
            if($Test_File -eq $true){
                Copy-Item -Path $File -Destination $Global:BackUp_Path -Force -Recurse -FromSession $PSSession 
                        }
                    }                     

#Folders Copy
$Folders = @('Desktop','Documents','Favorites','Links','Downloads','Music','Videos','Pictures','Contacts') 
    Foreach($Folder in $Folders){
        #Create Arugments for seperate thread
        $ArgumentsArray = $null

        $ArgumentsArray = @()
        $ArgumentsArray += "\\$Computer\c$\Users\$($User_List.name[$i])\$Folder"
        $ArgumentsArray += $Global:BackUp_Path
        $job = Start-Job -ScriptBlock { Copy-Item -Path $args[0] -Destination $args[1] -Force -Recurse } -Name $Folder -ArgumentList $ArgumentsArray 

        
        Register-ObjectEvent -InputObject $job -EventName StateChanged -Action {
        #Start-Sleep -Milliseconds 500
            $eventSubscriber | Unregister-Event
            $eventSubscriber.Action | Remove-Job
            if(-not (Get-EventSubscriber)){
                $Profile_Sum = Get-ChildItem -Path $Global:BackUp_Path -Recurse |
                    Measure-Object -Property length -Sum |
                    Select-Object -ExpandProperty Sum
                        $Size = try{if($Profile_Sum -lt 1048576){ $TinyByte = "  {0:N2}" -f ($Profile_Sum / 1KB) + " KB"; $TinyByte }
                        elseif($Profile_Sum -gt 1048576 -and $Profile_Sum -lt 1073741824){ $MediumByte = "  {0:N2}" -f ($Profile_Sum / 1MB) + " MB"; $MediumByte }
                        elseif($Profile_Sum -gt 1073741824){ $GiganticByte = "  {0:N2}" -f ($Profile_Sum / 1GB) + " GB"; $GiganticByte } } Catch {}
            
                $Begin_Time = Get-Item -Path $Global:BackUp_Path | Select-Object -ExpandProperty LastWriteTime
               
                $End_Time = Get-Date -Format G  

                Get-Job | Remove-Job 
                [System.Windows.MessageBox]::Show("Copying Complete!`nStart Time: $Begin_Time  `nEnd Time: $End_Time `nProfile Size copied: $Size")
                       
                        }
                    } | Out-Null 
                }

" "
Write-Output -InputObject "Copying will be done in background."
Write-Output -InputObject "You will be notified when copying is done."

            } catch [System.Management.Automation.Remoting.PSRemotingTransportException]{
                "Unable to connect to PC: $Computer `nError: $($Error[0].Exception.Message.Split('.')[2].Trim())!"
                }
            }
        }
    }

我删除了一些可能会给我带来麻烦的信息，但都是化妆品。（：

编辑： 我一定很忙，但是现在一切正常。我所做的唯一更改是在为其赋值之前清除全局变量 ($Global:var = $null)。谢谢大家的建议。我所做的另一项更改是将Copy-Item 更改为Robocopy。

Answer 1

只回答你的问题：

为什么我的 if 语句没有被正确读取？

就在您评估Get-EventSubscriber 之前，您正在取消您的活动订阅，从而删除您的活动订阅者。 Get-EventSubscriber 因此返回 $null，当被否定时，它的计算结果为 $true。总之，if 语句后面的代码总是会立即执行。

注释代码：

Register-ObjectEvent -InputObject $job -EventName StateChanged -Action {
    $eventSubscriber | Unregister-Event    # Here you cancel your event subscription
    $eventSubscriber.Action | Remove-Job
    if (-not (Get-EventSubscriber)) {      # Therefore, Get-EventSubscriber returns $null; not $null evaluates to $true
        ...

Unregister-Event文档中的相关部分：

Unregister-Event cmdlet 取消使用Register-EngineEvent、Register-ObjectEvent 或Register-WmiEvent cmdlet 创建的事件订阅。

取消事件订阅后，事件订阅者将从会话中删除，并且订阅的事件不再添加到事件队列中。当您取消订阅使用 New-Event cmdlet 创建的事件时，新事件也会从会话中删除。