powershell - 自定义睡眠功能可在不挂起时使 UI 睡眠 - 问题：计时器略微漂移

Question

我编写了一个自定义Start-SleepNoUIHang函数来休眠 Windows 窗体 UI，同时不挂起它以允许使用ForEach循环进行用户交互，并在该循环内调用它[System.Windows.Forms.Application]::DoEvents()以防止它这样做。

它按我的意图工作，但唯一的问题是函数稍微偏离了参数$Milliseconds。

如果我将其设置为说5000计时器大约需要6300几毫秒。

我试图在ForEach循环中添加一个计数器，然后在它到达$Milliseconds参数时退出它，但这似乎不起作用。

我不想使用 .net 计时器，所以我将它创建为单行，以便在程序中需要它的任何地方使用。

在这里的任何帮助将不胜感激。

这是代码（带注释）：

<#

This function attempts to pause the UI without hanging it without the need for a
timer event that does work.

The only trouble is that the timer slight drifts more than the provided
$Milliseconds argument.

#>

function Start-SleepNoUIHang {

  Param
  (
    [Parameter(Mandatory = $false, HelpMessage = 'The time to wait in milliseconds.')]
    [int]$Milliseconds
    )

  $timeBetween = 50 # This value seems to be a good value in order for the UI not to hang itself.
  $timeElapsed = 0 # Increment this to check and break out of the ForEach loop.

  # ($Milliseconds/$timeBetween)*$timeBetween # Time is the total wait time in milliseconds.

  1..($Milliseconds/$timeBetween) | ForEach {

    Start-Sleep -Milliseconds $timeBetween
    Try { [System.Windows.Forms.Application]::DoEvents() } catch{} # A try catch here in case there's no windows form.
    $timeElapsed = $timeElapsed + $timeBetween # Increment the $timeElapsed counter.

    Write-Host $timeElapsed

    # This doesn't seem to have any effect on the timer. It ends on its own accord.
    if ($timeElapsed -gt $Milliseconds) {
      Write-Host 'Break'
      break
    }

  }

}

$elapsed = [System.Diagnostics.Stopwatch]::StartNew()
Write-Host "Started at $(get-date)"

Start-SleepNoUIHang -Milliseconds 5000

Write-Host "Ended at $(get-date)"
Write-Host "Total Elapsed Time: $($elapsed.Elapsed.ToString())"

我也尝试过用这个替换 ForEach 循环的 While 循环，但行为相同。

  While ( $Milliseconds -gt $timeElapsed ) {

    $timeElapsed = $timeElapsed + $timeBetween # Increment the $timeElapsed counter.
    Start-Sleep -Milliseconds $timeBetween

    Write-Host $timeElapsed

  }

标签： powershell