为什么我的PowerShell脚本不遵守步骤顺序？

Question

我试图独自寻找解决方案，但现在我没有主意了。我写了一个脚本来检查计算机上是否安装了Erlang：

# Check if a Software ins installed
function Check_Program_Installed($programName) {
$x86_check = ((Get-ChildItem "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall") |
Get-ItemProperty |
        Where-Object {$_.DisplayName -like "*$programName*" } |
            Select-Object -Property DisplayName, UninstallString)

if(Test-Path 'HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall')  
{
$x64_check = ((Get-ChildItem "HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall") |
Get-ItemProperty |
        Where-Object {$_.DisplayName -like "*$programName*" } |
            Select-Object -Property DisplayName, UninstallString)
}
if ($x86_check -and $x64_check -eq $null){ 
    write-host "$programName is not installed on this computer" -ForegroundColor Green 
    #continue
    }
elseif ($x86_check -or $x64_check -ne $null){
    write-host "On this computer is installed " -ForegroundColor Red     
    $x86_check
    $x64_check

    }
}

# Erlang check
Write-Host "Checking if Erlang exist    " -NoNewline
Check_Program_Installed("Erlang")

Write-Host "The End: the script ends here" -ForegroundColor Yellow

但是如果我执行它的结果是最后一行在Check_Program_Installed("Erlang")之前执行。为什么PowerShell不遵守步骤优先级？

Checking if Erlang exist        On this computer is installed

The End: the script ends here
DisplayName          UninstallString
-----------          ---------------
Erlang OTP 21 (10.2) C:\Program Files\erl10.2\Uninstall.exe

Answer 1

我尝试复制您的代码并对其进行测试，但是我无法使实际的Check_Program_Installed函数正常工作，因此我很难进行验证。

但是，对于PowerShell，了解管道很重要。

通常，您所做的所有操作都会将其发送到管道，并按照管道获取的顺序显示在控制台中。

但是，Write-Host不会将您的文本发送到管道，而是直接将其发送到控制台，因此这可能是一种简单的竞争条件，其中文本到达控制台的速度比管道对象快。

如果您尝试使用Write-Output而不是Write-Host进行测试，我猜您会以正确的顺序得到它，因为Write-Output通过管道将对象发送到控制台。

Answer 2

只需在最后添加Format-Table到$ x86_check和$ 64_check。链接答案：https://social.technet.microsoft.com/Forums/en-US/5f88f7c9-fbce-4c45-a2fa-806d512a0233/powershell-output-wrong-order?forum=ITCG

# Check if a Software ins installed
function Check_Program_Installed($programName) {
$x86_check = ((Get-ChildItem "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall") |
Get-ItemProperty |
        Where-Object {$_.DisplayName -like "*$programName*" } |
            Select-Object -Property DisplayName, UninstallString) | Format-Table

if(Test-Path 'HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall')  
{
$x64_check = ((Get-ChildItem "HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall") |
Get-ItemProperty |
        Where-Object {$_.DisplayName -like "*$programName*" } |
            Select-Object -Property DisplayName, UninstallString) | Format-Table
}
if ($x86_check -and $x64_check -eq $null){ 
    write-host "$programName is not installed on this computer" -ForegroundColor Green 
    #continue
    }
elseif ($x86_check -or $x64_check -ne $null){
    write-host "On this computer is installed " -ForegroundColor Red     
    $x86_check
    $x64_check

    }

}

# Erlang check
Write-Host "Checking if Erlang exist    " -NoNewline
Check_Program_Installed("Erlang")
Write-Host "The End: the script ends here" -ForegroundColor Yellow