Powershell：如何在永无止境的脚本行之后继续运行脚本？

Question

I have a line in my script that downloads a large video file. After the download starts I want to already open the file while is it downloading. The problem is, is that the download command hasn't finished yet so the script stays stuck on the same line.

(Download-File command)

$allFiles = Get-ChildItem | Select-Object -Property name,LastAccessTime | measure-object -Property LastAccessTime -Maximum
$videoFile = Get-ChildItem | Where-Object { $_.LastAccessTime -eq $allFiles.Maximum}
Start-Process $videoFile

(I want this to run in a loop while the download-file command is running)

Answer 1

That should be easy. All you need to do is make it run on a different thread. Use background jobs or Runspaces. Below example is Background Job.

$ScriptBlock = {(Download-File command)}
Start-Job -ScriptBlock $ScriptBlock

do
{
    $allFiles = Get-ChildItem | Select-Object -Property name,LastAccessTime | measure-object -Property LastAccessTime -Maximum
    $videoFile = Get-ChildItem | Where-Object { $_.LastAccessTime -eq $allFiles.Maximum}
    Start-Process $videoFile
}
while (1 -gt 0)

Although, I am not sure if you would want to open the video file in a loop. If it does support opening an incomplete video file, you will have just as many instances of it. Better enclose it in an if (!(Get-Process -name $VideoFile)){} loop to prevent that.

Answer 2

Use the .waitforexit method.

Example:

$proc = Start-Process cmd.exe -PassThru
$proc.WaitForExit()

After the $proc.WaitForExit() line you can open your file.

Its look much better than a loop