Timeout of Read-Host in Powershell

问题

In Command Prompt, I'd throw the following into an iterated loop:

choice /c:abcdefghijklmnopqrstuvwxyz1234567890 /n /t:1 /d:0 
sleep 1

In Unix, I'd use: read -t 5 $input.

Does anyone know a way to do it in Powershell? Right now, I just wait it out (last line below).

I've set my script to switch between the TV and PC for my wife. I print a before and after for my wife and I'd like to bypass it for myself.

Here is my current script for context:

 $file_location = "C:\Users\krmar_000\Documents\audio.out"
 $current = gc $file_location
 Write-Host "Current Audio output: " -ForegroundColor White -NoNewline
 Write-Host $current -ForegroundColor Red

 Write-Host "Changing..." -ForegroundColor Yellow

 if ( $current -eq "Speakers” )
 {
     nircmd.exe mutesysvolume 0
     nircmd.exe setsysvolume 65535

     nircmd.exe setdefaultsounddevice “AMD HDMI Output”
     "AMD HDMI Output" | Out-File -filepath $file_location
 #    [System.Windows.Forms.MessageBox]::Show("TV Speakers enabled","Speaker Flip")

     Write-Host "TV Speakers enabled" -ForegroundColor Green
 }
 elseif ( $current -eq "AMD HDMI Output” )
 {
     nircmd.exe mutesysvolume 0
     nircmd.exe setsysvolume 52428

     nircmd.exe setdefaultsounddevice “Headset”
     "Speakers" | Out-File -filepath $file_location
 #    [System.Windows.Forms.MessageBox]::Show("Headset Speakers enabled","Speaker Flip")

     Write-Host "Headset Speakers enabled" -ForegroundColor Green
 }
 else
 {
     nircmd.exe setdefaultsounddevice “Speakers”
     "Speakers" | Out-File -filepath $file_location
 #    [System.Windows.Forms.MessageBox]::Show("Headset Speakers enabled","Speaker Flip")    

     Write-Host "Headset Speakers enabled" -ForegroundColor Green 
 }
 Start-Sleep -Seconds 5

回答1:

It's not exactly a dupe of the linked answer, but it's pretty close. Full function here (based loosely on same) for convenience:

function Read-HostWithDelay {
  param([Parameter(Mandatory=$true)][int]$Delay, [string]$Prompt, [Switch]$AsSecureString)
  [int]$CSecDelayed = 0
  do {
    [bool]$BReady = $host.UI.RawUI.KeyAvailable
    [Threading.Thread]::Sleep(1000)
  } while (!$BReady -and ($CSecDelayed++ -lt $Delay))
  if ($BReady -and $Prompt) { Read-Host $Prompt -AsSecureString:$AsSecureString }
  # No, Read-Host will not in fact handle null parameter binding (-Prompt:$Prompt) properly. Who knows why not.
  elseif ($BReady) { Read-Host -AsSecureString:$AsSecureString }      
}

Tested, and a good thing too, as it proved just a touch less trivial than I'd frankly expected.

来源：https://stackoverflow.com/questions/27455221/timeout-of-read-host-in-powershell

标签

powershell

sleep