调用调用-表达的参数在PowerShell中 [英] calling Invoke-Expression with Parameters in Powershell

问题描述

我已经写在C＃的PowerShell模块，有一堆的cmdlet像

I've written a powershell module in c# that has a bunch of cmdlets like

添加-VM

的cmdlet接触到的API，并提取数据回来。

The cmdlets reach out to an API and pull data back.

但统一起见与产品的SSH CLI，我写了一个调用的函数newtask接受addvm作为一个参数和的$ args。

but for the sake of uniformity with the ssh CLI of the product, i've written a function called newtask that accepts 'addvm' as an argument and $args.

例如：

newtask addvm -id 12345

我然后调用添加-VM，并传递的$ args作为字符串像这样

I then invoke Add-VM and pass $args as a string like so

Invoke-Expression Add-VM $argstr

的问题是，添加虚拟机抛出一个错误，它无法找到接受参数System.Object的[]

The problem is that Add-VM throws an error that it cannot find a positional parameter that accepts argument System.Object[]

一个位置参数无法找到接受参数'System.Object的[]

A positional parameter cannot be found that accepts argument 'System.Object[]'

虽然我可以很容易别名'addvm'到'添加虚拟机，我试图保持与SSH CLI均匀性，使新用户能够迅速开始利用这个模块。

While I could easily alias 'addvm' to 'Add-VM', i'm trying to maintain uniformity with the ssh CLI so that new users can quickly start utilizing this module.

我想，发送一个字符串，如-id 12345'就足够了，但事实并非如此。是否pscmdlet期望获得什么东西？

I figured that sending a string like '-id 12345' would suffice but it's not. Does the pscmdlet expect to receive something else?

在此先感谢。

推荐答案

这是错误来自调用，表达不添加虚拟机，你只需要大约参数报价：

That error is from Invoke-Expression not Add-VM and you just need quotes around the argument:

Invoke-Expression "Add-VM $argstr"

这具有迫使所有对象为字符串格式的缺点。这可能是简单的类型，如整型和字符串可以接受的，但如果你想通过一个更复杂的对象，它不会工作。另一种方法是，以图示与 @args 的论点，但我不认为你可以通过调用-表达做到这一点或调用命令。您需要直接调用该cmdlet：

This has the drawback of forcing all objects into string format. This might be acceptable for simple types like ints and strings but if you want to pass through a more complex object it won't work. An alternative would be to splat the arguments with @args but I don't think you can do this through Invoke-Expression or Invoke-Command. You need to directly call the cmdlet:

function newtask {
    params([string]$command)

    switch ($command) {
        "addvm" { Add-VM @args }
        "deletevm" { Remove-VM @args }
    }
}

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