Powershell GUI 冻结，即使有运行空间

Question

我正在创建一个带有 GUI 的 powershell 脚本，它将用户配置文件从 selected 源磁盘复制到目标磁盘。我在 XAML 中使用 VS Community 2019 创建了 GUI。该脚本的工作方式如下：您 select 源磁盘、目标磁盘、用户配置文件和要复制的文件夹。当您按下“开始”按钮时，它会调用一个名为 Backup_data 的函数，其中会创建一个运行空间。在此运行空间中，只有一小部分 Copy-Item， 将您 selected.

作为参数

脚本运行良好，所有需要的项目都已正确复制。问题是 GUI 在复制过程中冻结（没有“未响应”消息或其他任何消息，它只是完全冻结；无法单击任何地方，无法移动 window）。我已经看到使用运行空间可以解决这个问题，但对我来说不是。我错过了什么吗？

这是函数 Backup_Data:

Function BackupData {  
  ##CREATE RUNSPACE
  $PowerShell = [powershell]::Create()
  [void]$PowerShell.AddScript( {
      Param ($global:ReturnedDiskSource, $global:SelectedUser, $global:SelectedFolders, $global:ReturnedDiskDestination)
      ##SCRIPT BLOCK
      foreach ($item in $global:SelectedFolders) {
        Copy-Item -Path "$global:ReturnedDiskSource\Users$global:SelectedUser$item" -Destination "$global:ReturnedDiskDestination\Users$global:SelectedUser$item" -Force -Recurse
      }
    }).AddArgument($global:ReturnedDiskSource).AddArgument($global:SelectedUser).AddArgument($global:SelectedFolders).AddArgument($global:ReturnedDiskDestination)
  #Invoke the command
  $PowerShell.Invoke()
  $PowerShell.Dispose()
}

Answer 1

PowerShell SDK 的 PowerShell.Invoke() 方法是同步，因此设计 blocks 而脚本在另一个运行空间（线程）运行s.

您必须改用异步PowerShell.BeginInvoke()方法。

简单示例图中没有WPF（WPF解决方案见底部）：

$ps = [powershell]::Create()

# Add the script and invoke it *asynchronously*
$asyncResult = $ps.AddScript({ Start-Sleep 3; 'done' }).BeginInvoke()

# Wait in a loop and check periodically if the script has completed.
Write-Host -NoNewline 'Doing other things..'
while (-not $asyncResult.IsCompleted) {
  Write-Host -NoNewline .
  Start-Sleep 1
}
Write-Host

# Get the script's success output.
"result: " + $ps.EndInvoke($asyncResult)

$ps.Dispose()

请注意，有一个比使用 PowerShell SDK 更简单的替代方法：ThreadJob 模块的 Start-ThreadJob cmdlet, a thread-based alternative to the child-process-based regular background jobs started with Start-Job，与所有兼容其他 *-Job cmdlet。

Start-ThreadJob 附带 PowerShell [Core] 7+，可以从 Windows 中的 PowerShell Gallery 安装] PowerShell (Install-Module ThreadJob).

# Requires module ThreadJob (preinstalled in v6+)

# Start the thread job, always asynchronously.
$threadJob = Start-ThreadJob { Start-Sleep 3; 'done' }

# Wait in a loop and check periodically if the job has terminated.
Write-Host -NoNewline 'Doing other things..'
while ($threadJob.State -notin 'Completed', 'Failed') {
  Write-Host -NoNewline .
  Start-Sleep 1
}
Write-Host

# Get the job's success output.
"result: " + ($threadJob | Receive-Job -Wait -AutoRemoveJob)

完整示例 with WPF:

如果像您的情况一样，代码需要运行来自附加到 WPF window 控件的事件处理程序，则需要做更多的工作，因为 Start-Sleep 可以不使用，因为它 阻止 GUI 事件的处理 并因此冻结 window.

与 WinForms 不同，后者具有用于按需处理未决 GUI 事件的内置方法 ([System.Windows.Forms.Application]::DoEvents(), WPF has no equivalent method, but it can be added manually, as shown in the DispatcherFrame documentation.

下面的例子：

创建一个 window，带有两个后台操作启动按钮和相应的状态文本框。
使用按钮单击事件处理程序通过 Start-ThreadJob:
启动后台操作
- 注意：Start-Job 也可以，但是运行 子进程 而不是线程中的代码，这要慢得多并且有其他重要的后果。
- 使该示例适应 PowerShell SDK ([powershell]) 的使用也不难，但是线程作业更符合 PowerShell 惯用方式并且更易于管理，通过常规 *-Job cmdlet。
显示 WPF window非-模态并进入自定义事件循环：
- A custom DoEvents()-like 函数，DoWpfEvents，改编自 DispatcherFrame documentation 在每个循环中调用用于 GUI 事件处理的操作。
  - 注意：对于 WinForms 代码，您可以简单地调用 [System.Windows.Forms.Application]::DoEvents().
- 此外，监控后台线程作业的进度，并将收到的输出附加到特定于作业的状态文本框。已完成的作业已清理。

注意：就像调用window 模态（使用.ShowModal()）一样，显示 window 时，前台线程和控制台会话被阻塞。避免这种情况的最简单方法是运行隐藏子进程中的代码；假设代码在脚本中 wpfDemo.ps1:

# In PowerShell [Core] 7+, use `pwsh` instead of `powershell`
Start-Process -WindowStyle Hidden powershell '-noprofile -file wpfDemo.ps1'

^{您也可以通过 SDK 完成此操作，这样速度会更快，但更加冗长和繁琐：

$runspace = [runspacefactory]::CreateRunspace() $runspace.ApartmentState = 'STA'; $runspace.Open(); $ps = [powershell]::Create(); $ps.Runspace = $runspace; $null = $ps.AddScript((Get-Content -Raw wpfDemo.ps1)).BeginInvoke()}

截图:

此示例屏幕截图显示了一项已完成的后台操作和一项正在进行的操作（运行将它们并行支持）；请注意启动正在进行的操作的按钮在操作期间是如何被禁用的，以防止重新进入：

源代码：

using namespace System.Windows
using namespace System.Windows.Threading

# Load WPF assemblies.
Add-Type -AssemblyName PresentationCore, PresentationFramework

# Define the XAML document, containing a pair of background-operation-launching
# buttons plus associated status text boxes.
[xml] $xaml = @"
<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Test"
        Title="MainWindow" Height="220" Width="600">
    <Grid>
        <TextBox x:Name="Status1" Height="140" Width="280" Margin="10,10" TextWrapping="Wrap" VerticalAlignment="Top" HorizontalAlignment="Left" AcceptsReturn="True" AcceptsTab="True" Padding="4" VerticalScrollBarVisibility="Auto" />
        <TextBox x:Name="Status2" Height="140" Width="280" Margin="10,10" TextWrapping="Wrap" VerticalAlignment="Top" HorizontalAlignment="Right" AcceptsReturn="True" AcceptsTab="True" Padding="4" VerticalScrollBarVisibility="Auto" />
        <Button x:Name="DoThing1" Content="Do Thing 1" HorizontalAlignment="Left" VerticalAlignment="Bottom" Width="100" Height="22" Margin="10,5" IsDefault="True" />
        <Button x:Name="DoThing2" Content="Do Thing 2" HorizontalAlignment="Right" VerticalAlignment="Bottom" Width="100" Height="22" Margin="10,5" />
    </Grid>
</Window>
"@

# Parse the XAML, which returns a [System.Windows.Window] instance.
$Window = [Markup.XamlReader]::Load((New-Object System.Xml.XmlNodeReader $xaml))

# Save the window's relevant controls in PowerShell variables.
# Background-operation-launching buttons.
$btns = $Window.FindName('DoThing1'), $Window.FindName('DoThing2')

# Use a [hashtable] to map the buttons to the associated status text boxes.
$txtBoxes = @{
  $btns[0] = $Window.FindName('Status1')
  $btns[1] = $Window.FindName('Status2')
}
# Use a [hashtable] to map the buttons to the associated background
# operations, defined as script blocks to be passed to Start-ThreadJob later.
# The sample operations here run for a few seconds, 
# emitting '.' every second and a message on completion.
$scriptBlocks = @{
  $btns[0] = 
    {
      1..3 | ForEach-Object { '.'; Start-Sleep 1 }
      'Thing 1 is done.'
    }
  $btns[1] = 
    {
      1..2 | ForEach-Object { '.'; Start-Sleep 1 }
      'Thing 2 is done.'
    }
}

# Attach the button-click event handlers that
# launch the background operations (thread jobs).
foreach ($btn in $btns) {

  $btn.Add_Click({

    # Temporarily disable this button to prevent re-entry.
    $this.IsEnabled = $false

    # Show a status message in the associated text box.
    $txtBoxes[$this].Text = "Started thing $($this.Name -replace '\D') at $(Get-Date -Format T)."

    # Asynchronously start a background thread job named for this button.
    # Note: Would work with Start-Job too, but that runs the code in *child process*, 
    #       which is much slower and has other implications.
    $null = Start-ThreadJob -Name $this.Name $scriptBlocks[$this]

  })

}

# Define a custom DoEvents()-like function that processes GUI WPF events and can be 
# called in a custom event loop in the foreground thread.
# Adapted from: https://docs.microsoft.com/en-us/dotnet/api/system.windows.threading.dispatcherframe
function DoWpfEvents {
  [DispatcherFrame] $frame = [DispatcherFrame]::new($True)
  $null = [Dispatcher]::CurrentDispatcher.BeginInvoke(
    'Background', 
    [DispatcherOperationCallback] {
      param([object] $f)
      ($f -as [DispatcherFrame]).Continue = $false
      return $null
    }, 
    $frame)
  [Dispatcher]::PushFrame($frame)
}


# Finally, display the window NON-modally...
$Window.Show() 
$null = $Windows.Activate() # Ensures that the window gets the focus.
# ... and enter a custom event loop based on calling the custom .DoEvents() method
while ($Window.IsVisible) {

  # Process GUI events.
  DoWpfEvents

  # Process pending background (thread) jobs, if any.
  Get-Job | ForEach-Object {
    
    # Get the originating button via the job name.
    $btn = $Window.FindName($_.Name)
    # Get the corresponding status text box.
    $txtBox = $txtBoxes[$btn]

    # Test if the job has terminated.
    $completed = $_.State -in 'Completed', 'Failed', 'Stopped'

    # Append any new results to the respective status text boxes.
    # Note the use of redirection *>&1 to capture ALL streams, notably including the error stream.
    if ($data = Receive-Job $_ *>&1) {
      $txtBox.Text += "`n" + ($data -join "`n")
    }

    # Clean up, if the job is completed.
    if ($completed) {
      Remove-Job $_
      $btn.IsEnabled = $true # re-enable the button.
      $txtBox.Text += "`nJob terminated on: $(Get-Date -Format T); status: $($_.State)."
    }

  }

  # Note: If there are no GUI events pending, this loop will cycle very rapidly.
  #       To mitigate this, we *also* sleep a little, but short enough to still keep
  #       the GUI responsive.
  Start-Sleep -Milliseconds 50

}

# Window was closed; clean up:
# If the window was closed before all jobs completed, 
# get the incomplete jobs' remaining output, wait for them to finish, and delete them.
Get-Job | Receive-Job -Wait -AutoRemoveJob

Answer 2

我一整天都在寻找解决方案，终于找到了，所以我要 post 把它提供给有同样问题的人。

首先，查看这篇文章：https://smsagent.blog/2015/09/07/powershell-tip-utilizing-runspaces-for-responsive-wpf-gui-applications/ 它得到了很好的解释，并向您展示了如何通过 WPF GUI 正确使用运行空间。您只需将 $Window 变量替换为 $Synchhash.Window :

$syncHash = [hashtable]::Synchronized(@{})
$reader = (New-Object System.Xml.XmlNodeReader $xaml)
$syncHash.window = [Windows.Markup.XamlReader]::Load( $reader )

在您的代码中插入运行空间函数：

function RunspaceBackupData {
$Runspace = [runspacefactory]::CreateRunspace()
$Runspace.ApartmentState = "STA"
$Runspace.ThreadOptions = "ReuseThread"
$Runspace.Open()
$Runspace.SessionStateProxy.SetVariable("syncHash",$syncHash)
$Runspace.SessionStateProxy.SetVariable("SelectedFolders",$global:SelectedFolders)
$Runspace.SessionStateProxy.SetVariable("SelectedUser",$global:SelectedUser)
$Runspace.SessionStateProxy.SetVariable("ReturnedDiskSource",$global:ReturnedDiskSource)
$Runspace.SessionStateProxy.SetVariable("ReturnedDiskDestination",$global:ReturnedDiskDestination)
$code = {
    foreach ($item in $global:SelectedFolders) {
        copy-item -Path "$global:ReturnedDiskSource\Users$global:SelectedUser$item" -Destination "$global:ReturnedDiskDestination\Users$global:SelectedUser$item" -Force -Recurse
        }
}
$PSinstance = [powershell]::Create().AddScript($Code)
$PSinstance.Runspace = $Runspace
$job = $PSinstance.BeginInvoke()
}

然后使用您指定的参数在您想要的事件处理程序中调用它：

$var_btnStart.Add_Click( {
    RunspaceBackupData -syncHash $syncHash -SelectedFolders $global:SelectedFolders -SelectedUser $global:SelectedUser -ReturnedDiskSource $global:ReturnedDiskSource -ReturnedDiskDestination $global:ReturnedDiskDestination 
})

别忘了结束你的运行空间：

$syncHash.window.ShowDialog()
$Runspace.Close()
$Runspace.Dispose()

Powershell GUI 冻结，即使有运行空间

Powershell GUI Freezing, even with runspace

wpf

powershell

xaml

powershell-sdk

runspace