Powershell如何在Start-Job的Scriptblock裏傳參？

如何在Start-Job的Scriptblock裏傳參？

方法1：

利用本地變量，從一個可擴展的字符串，使用[scriptblock]::create方法建立腳本塊：

$v1 = "123"
$v2 = "asdf"
$sb = [scriptblock]::Create("Write-Host 'Values are: $v1, $v2'")
$job = Start-Job -ScriptBlock $sb

# 另外一種寫法
[scriptblock]$sb =
{
Write-Host "Values are: $v1, $v2"
}

方法2：

在InitializationScript中設置變量

$Init_Script = {
$v1 = "123"
$v2 = "asdf"
}
$sb = {
    Write-Host "Values are: $v1, $v2"
}
$job = Start-Job -InitializationScript $Init_Script -ScriptBlock $sb

方法3：

使用-Argumentlist參數

$v1 = "123"
$v2 = "asdf"
$sb = {
    Write-Host "Values are: $($args[0]), $($args[1])"
}
$job = Start-Job  -ScriptBlock $sb -ArgumentList $v1,$v2

深刻閱讀

Using scope

PowerShell v3 introduced another level of scope called using. It doesn’t fit into the
hierarchical model described in figure 22.1, and the rules laid down in this chapter
don’t apply, because it’s designed to be used in situations where you want to access
a local variable in a remote session. The definition from the help file about_scopes is:
Using is a special scope modifier that identifies a local variable in a remote
command. By default, variables in remote commands are assumed to be defined
in the remote session.

More on using can be found in about_Remote_Variables. It’s used like this:
PS C:\> $s = New-PSSession -ComputerName W12Standard
PS C:\> $dt = 3
PS C:\> Invoke-Command -Session $s -ScriptBlock {Get-WmiObject -Class
➥ Win32_LogicalDisk -Filter "DriveType=$dt"}

Invalid query "select * from Win32_LogicalDisk where DriveType="
+ CategoryInfo : InvalidArgument: (:)
[Get-WmiObject], ManagementException
+ FullyQualifiedErrorId : GetWMIManagementException,
Microsoft.PowerShell.Commands.GetWmiObjectCommand
+ PSComputerName : W12Standard

PS C:\> Invoke-Command -Session $s -ScriptBlock {Get-WmiObject -Class
➥ Win32_LogicalDisk -Filter "DriveType=$Using:dt"}
DeviceID : C:
DriveType : 3
ProviderName :
FreeSpace : 126600425472
Size : 135994011648
VolumeName :
PSComputerName : W12Standard

Create a remoting session to another machine and define a local variable. If you try
to use that variable (which is local) in the remote session, you’ll get the error shown
in the first command, but if you employ the using scope, it works.
In PowerShell v2, you could do this:
PS C:\> Invoke-Command -Session $s -ScriptBlock {param($d) Get-
➥ WmiObject -Class Win32_LogicalDisk -Filter "DriveType=$d" }
➥ -ArgumentList $dt

Using is a valuable addition to your toolbox when you’re working with remote machines.