PowerShell调用CMD执行exe时如何将实时输出流式传递给函数

你遇到的输出无法实时传递的核心原因是：支持管道输入的PowerShell自定义函数，必须显式声明process块才能逐行处理管道输入，否则函数默认会等待所有管道输入全部接收完成后，才会一次性执行函数逻辑。
而Out-Host是PowerShell原生命令，内部已经实现了逐行处理的逻辑，所以可以实时显示输出。

步骤1：修改自定义函数，新增process块 #

将你原本写在函数体里的所有处理逻辑，包裹到process {}块内，这样每收到一行管道输入就会立即执行一次处理逻辑：

function get-ValidateProgress
{
     param ([Parameter(Mandatory,HelpMessage='Value Passed from ValidateLDS.exe',Position=0,ValueFromPipeline)]$ValidateLine)
     # 新增process块，包裹所有处理逻辑
     process {
         IF($ValidateLine -like 'Proccessing Active Users record*' )
         {
            $Current=$ValidateLine -replace 'Proccessing Active Users record ','' -replace 'of.*','' -replace ' ',''
            $TotalValue=$ValidateLine -replace "Proccessing Active Users record $Current of " ,''
            [INT]$Progress=(($Current/$TotalValue)*100)
            Write-Progress -Id 1 -Activity ValidateDBLDS -Status 'Proccessing LDS User records' -PercentComplete $Progress -CurrentOperation 'Active Users'
            IF($Current -eq $TotalValue){write-host 'Finished procccsing Active Users' -ForegroundColor Green}
         }
         ELSEIF($ValidateLine -like 'Proccessing Deleted Users record*' )
         {
            $Current=$ValidateLine -replace 'Proccessing Deleted Users record ','' -replace 'of.*','' -replace ' ',''
            $TotalValue=$ValidateLine -replace "Proccessing Deleted Users record $Current of " ,''
            [INT]$Progress=(($Current/$TotalValue)*100)
            Write-Progress -Id 1 -Activity ValidateDBLDS -Status 'Proccessing LDS User records' -PercentComplete $Progress -CurrentOperation 'Deleted Users'
            IF($Current -eq $TotalValue){write-host 'Finished procccsing Deleted Users' -ForegroundColor Green}
         }
         # 如果需要保留输出到变量，可以加一行返回$ValidateLine
         $ValidateLine
     }
}

步骤2：调整调用逻辑 #

你原代码中将管道结果赋值给$cmdOutput的操作，会触发PowerShell等待整个管道执行完成才返回结果，如果不需要保存执行输出可以直接去掉赋值，如果需要保存输出，保留赋值即可，配合上面修改后的函数依然可以实时处理进度：

Try{
# 如果不需要保存输出，直接执行即可
cmd.exe /c "cd /d D:\$Campus\Code\Utilities && ValidateDBLDS.exe /viewonly:false" 2>&1 | get-ValidateProgress
# 如果需要保存输出，保留赋值即可，进度依然会实时更新
# $cmdOutput = cmd.exe /c "cd /d D:\$Campus\Code\Utilities && ValidateDBLDS.exe /viewonly:false" 2>&1 | get-ValidateProgress

Write-Host "Successfully finished LDS Validation." -ForegroundColor Green
sleep -Seconds 2
}
Catch{
Write-host "An Error occured during validating LDS. See full expection below.`nExecption:"$Error[0].Exception"`nTargetObject:"$Error[0].TargetObject"`nInvocationInfo:"$Error[0].InvocationInfo -ForegroundColor Red
}

你可以不需要调用cmd.exe切换路径执行程序，直接在PowerShell中指定工作目录调用exe即可：

$workDir = "D:\$Campus\Code\Utilities"
& "$workDir\ValidateDBLDS.exe" /viewonly:false 2>&1 | get-ValidateProgress

内容的提问来源于stack exchange，提问作者Elior Machlev