Powershell Start-Job调用带有参数的函数参数 [英] Powershell Start-job invoke function argument with parameter

问题描述

我有一个具有两个参数的函数mainFunction-$name将只是一个常规字符串，而$moveFunction将是一些函数.

I have a function mainFunction that gets 2 parameters - $name will be just a regular string, and $moveFunction will be some function.

我想开始一个ScriptBlock($SB)的工作，该脚本将以$name作为参数来调用$moveFunction.

I want to start a job of a ScriptBlock ($SB) that will invoke $moveFunction with $name as his argument.

function foo($a){
    Write-Output "In function foo with the argument => $a"
}

$SB = { 
        param($C, $fooFunction)
        $fooFunction.Invoke($C)
     } 

function mainFunction($name, $moveFunction){
    Start-Job  -Name "currentJob" -ArgumentList $name, ${Function:$moveFunction} -ScriptBlock $SB

}


$j1 = mainFunction -name "output!" -moveFunction $Function:foo

我检查mainFunction中是否已经存在$moveFunction(在mainFunction处的$moveFunction.invoke(5))

I checked that $moveFunction exists in mainFunction already ($moveFunction.invoke(5) at mainFunction)

在开始工作时将函数作为参数传递时，我找不到问题.

I can't find the problem in passing the function as argument in the start-job.

，然后从Get-Job -Name "CurrentJob" | Receive-Job我得到:

You cannot call a method on a null-valued expression.
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull
    + PSComputerName        : localhost

任何帮助将不胜感激.

Any help would be appreciated.

问题很可能是我将函数作为参数传递的方式(${Function:$moveFunction}

edit: The problem is most likely the way I pass the function as an argument (${Function:$moveFunction}

推荐答案

仅是对我之前的注释和代码示例进行了重新混编.类似的问题此处.本质上，传递给Jobs和Remote命令的参数是序列化的.在反序列化过程中，函数和脚本块以字符串形式出现，而不是其原始类型.幸运的是，使用[ScriptBlock]::Create("string")将它们转换为可调用的脚本块是一个简单的过程.

Just a rehash of my previous comment plus code example. Similar issue here. Essentially, arguments passed to Jobs and Remote commands are serialized. During the de-serialization process, functions and script blocks come out as strings instead of their original type. Fortunately it's a simple process to transform these into invokable scriptblocks using [ScriptBlock]::Create("string").

function foo {
    write-host "foo"
}

function bar {
    # This argument comes in as a string
    param($func)
    write-host "bar"

    # Create scriptblock from string
    $func = [ScriptBlock]::Create($func)
    $func.invoke()
}

Start-Job -ArgumentList $Function:Foo -ScriptBlock $Function:Bar

Get-Job | Wait-job
Get-Job | Receive-job

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