PowerShell函数抛出空异常 [英] Powershell function throwing null exception

问题描述

好吧，我已经阅读了关于调用函数并在PowerShell中传递参数的问题，但也许我不理解某些东西。我正在调用一个函数并传递几个参数，一切正常。它是在函数中定义的变量，当它不是时，它似乎为空。

函数：

 function get-session {
 $ session = New-PSSession -ComputerName $ ip -Credential $ cred -Auth CredSSP 
 $ subcomps ='COMP1'
 foreach （$子计算机中的$ Computer）
 {
 $计算机
 Invoke-Command -Session $ session -ScriptBlock {Get-WmiObject -ComputerName $计算机 - 查询SELECT * FROM Win32_Group} 
 
 Remove-PSSession -ComputerName $ ip 
 
 $ / code> 

脚本：

  $ ip ='123.45.67.89'
 $ ComputerName =HOPCOMP
 $ user =' \Admin'
 $ cred = $ ComputerName + $ user 
 $ ip 
 $ cred 
（get-session -ComputerName $ ip -Credential $ cred）
  

当我执行此操作时：

 无法验证参数'ComputerName'的参数。参数为空或空。 
提供一个非空或空的参数，然后再次尝试该命令。 
 + CategoryInfo：InvalidData：（:) [Get-WmiObject]，ParameterBindingValidationException 
 + FullyQualifiedErrorId：ParameterArgumentValidationError，Microsoft.PowerShell.Commands.GetWmiObjectCommand 
  

当然，如果我将函数Get-WMIObject行中的$ Computer更改为COMP1，则一切正常。但是，在$ foreach循环中写出的$ Computer会成功写入COMP1。

我在这里缺少什么？

解决方案

您需要使用Invoke-Command指定-ArgumentList参数。例如：
$ b $ pre $ Invoke-Command -Session $ session -ScriptBlock {param（$ Computer）Get-WmiObject -ComputerName $ Computer - QuerySELECT * FROM Win32_Group} -ArgumentList $ Computer


Okay, so I've read up on calling functions and passing parameters in powershell but maybe I'm not understanding something. I am calling a function and passing a couple parameters and everything works fine. It is variable defined within the function that seems to be null when it isn't.

Function:

function get-session {
$session = New-PSSession -ComputerName $ip -Credential $cred -Auth CredSSP
$subcomps = 'COMP1'
foreach ($Computer in $subcomps)
{
$Computer
Invoke-Command -Session $session -ScriptBlock { Get-WmiObject -ComputerName $Computer -Query "SELECT * FROM Win32_Group" }
}
Remove-PSSession -ComputerName $ip
}

Script:

$ip = '123.45.67.89'
$ComputerName = "HOPCOMP"
$user = '\Admin'
$cred = $ComputerName + $user
$ip
$cred
(get-session -ComputerName $ip -Credential $cred)

When I run this:

Cannot validate argument on parameter 'ComputerName'. The argument is null or empty.
Supply an argument that is not null or empty and then try the command again.
+ CategoryInfo          : InvalidData: (:) [Get-WmiObject], ParameterBindingValidationException
+ FullyQualifiedErrorId : ParameterArgumentValidationError,Microsoft.PowerShell.Commands.GetWmiObjectCommand

Of course, if I change $Computer in in the function Get-WMIObject line to COMP1 everything works great. But, the $Computer write out in the foreach loop writes COMP1 successfully.

What am I missing here?

解决方案

You need to specify the -ArgumentList parameter with your Invoke-Command. For example:

Invoke-Command -Session $session -ScriptBlock { param($Computer) Get-WmiObject -ComputerName $Computer -Query "SELECT * FROM Win32_Group" } -ArgumentList $Computer

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