如何将 System.Collections.ArrayList 添加到 PowerShell 自定义对象？

Question

我的目标是创建一个自定义数据对象，它有两个离散变量（fooName 和 fooUrl）和一个 fooChildren 列表，每个列表项都有两个离散变量变量childAge 和 childName.

目前，我有这个：

$fooCollection = [PSCustomObject] @{fooName=""; fooUrl=""; fooChildrenList=@()} 

$fooCollection.fooName = "foo-a-rama"
$fooCollection.fooUrl = "https://1.2.3.4"

$fooChild = New-Object -TypeName PSobject
$fooChild | Add-Member -Name childAge -MemberType NoteProperty -Value 6
$fooChild | Add-Member -Name childName -MemberType NoteProperty -Value "Betsy"
$fooCollection.fooChildrenList += $fooChild

$fooChild = New-Object -TypeName PSobject
$fooChild | Add-Member -Name childAge -MemberType NoteProperty -Value 10
$fooChild | Add-Member -Name childName -MemberType NoteProperty -Value "Rolf"
$fooCollection.fooChildrenList += $fooChild

cls
$fooCollection.fooName
$fooCollection.fooUrl

foreach ($fooChild in $fooCollection.fooChildrenList)
{
    ("  " + $fooChild.childName + " " + $fooChild.childAge)
}

产生以下内容。到目前为止一切顺利

foo-a-rama
https://1.2.3.4
  Betsy 6
  Rolf 10

问题：我不喜欢使用 += 因为据我所知，使用 += 会导致 $fooCollection.fooChildrenList 的副本每次执行 += 时都会创建（处于任何状态）。

因此，我不想将 fooChildrenList 实现为 @()，而是将 fooChildrenList 实现为 New-Object System.Collections.ArrayList，这样我就可以根据需要添加每一行。我已经在代码中尝试了多种方法来执行此操作，但 fooChildrenList 最终无人问津。例如：

$fooCollection = [PSCustomObject] @{fooName=""; fooUrl=""; fooChildrenList = New-Object System.Collections.ArrayList} 

$fooCollection.fooName = "foo-a-rama"
$fooCollection.fooUrl = "https://1.2.3.4"

$fooChild.childName = "Betsy"
$fooChild.childAge = 6
$fooCollection.fooChildrenList.Add((New-Object PSObject -Property $fooChild))

$fooChild.childName = "Rolf"
$fooChild.childAge = 10
$fooCollection.fooChildrenList.Add((New-Object PSObject -Property $fooChild))

$fooCollection | get-member 显示

TypeName: System.Management.Automation.PSCustomObject

Name            MemberType   Definition                                   
----            ----------   ----------                                   
Equals          Method       bool Equals(System.Object obj)               
GetHashCode     Method       int GetHashCode()                            
GetType         Method       type GetType()                               
ToString        Method       string ToString()                            
fooChildrenList NoteProperty System.Collections.ArrayList fooChildrenList=
fooName         NoteProperty string fooName=foo-a-rama                    
fooUrl          NoteProperty string fooUrl=https://1.2.3.4

$fooCollection 显示

fooName         : foo-a-rama
fooUrl          : https://1.2.3.4
fooChildrenList : {}

如何将 System.Collections.ArrayList 添加到 PowerShell 自定义对象？

Answer 1

从我用来制作一些数组的东西中快速复制粘贴。我必须创建自定义对象，然后将它们添加到数组中。它需要根据您的情况进行修改，但我认为它会满足您的需求。

[System.Collections.ArrayList]$SQL_Query_Results = @()

ForEach ($SQL_Index in $SQL_Table) {

    $SQL_Array_Object = [PSCustomObject]@{
        'Computer_Name'    = $SQL_Table[$SQL_Index_Counter].ComputerID -replace ",", ""
        'Project'          = $SQL_Table[$SQL_Index_Counter].Project
        'Site'             = $SQL_Table[$SQL_Index_Counter].Site
        'Description'      = $SQL_Table[$SQL_Index_Counter].Description -replace ",", ""
        'Physical_Machine' = $SQL_Table[$SQL_Index_Counter].IsPhysicalMachine
        'Active'           = $SQL_Table[$SQL_Index_Counter].IsActive
    }

    $SQL_Query_Results.Add($SQL_Array_Object) | Out-Null
}

经过编辑以显示 Array 最初是如何创建的。

Answer 2

嗯，我不确定你遇到了什么问题，它对我来说很好

function New-Child([string]$Name, [int]$Age){
    $Child = New-Object -TypeName PSobject
    $Child | Add-Member -Name childAge -MemberType NoteProperty -Value $age -PassThru | 
    Add-Member -Name childName -MemberType NoteProperty -Value $name
    return $child
}

$fooCollection = [PSCustomObject] @{fooName=""; fooUrl=""; fooChildrenList = New-Object System.Collections.ArrayList} 

$fooCollection.fooName = "foo-a-rama"
$fooCollection.fooUrl = "https://1.2.3.4"
$fooCollection.fooChildrenList.Add((New-Child -Name "Betty" -Age 9)) | Out-Null
$fooCollection.fooChildrenList.Add((New-Child -Name "Ralf" -Age 15)) | Out-Null

$fooCollection.fooName
$fooCollection.fooUrl
foreach ($fooChild in $fooCollection.fooChildrenList)
{
    "  " + $fooChild.childName + " " + $fooChild.childAge
}

输出

foo-a-rama
https://1.2.3.4
  Betty 9
  Ralf 15

Answer 3

挑战是添加一个副本 $fooChild [pscustomobject] 实例，你重新- using 每次用 .Add() 添加到列表 时（如果不使用副本，最终所有列表元素都指向相同对象）。

但是，您不能使用 New-Object PSObject -Property.[=28 克隆现有的 [pscustomobject] (a.k.a [psobject]) 实例=]

一个选项 (PSv3+) 是将可重用 $fooChild 定义为 有序哈希表 ，然后使用 [pscustomobject] cast，每次隐式创建一个新对象：

$fooCollection = [PSCustomObject] @{ fooChildrenList = New-Object Collections.ArrayList } 

# Create the reusable $fooChild as an *ordered hashtable* (PSv3+)
$fooChild = [ordered] @{ childName = ''; childAge = -1 }

# Create 1st child and add to list with [pscustomobject] cast
$fooChild.childName = 'Betsy'; $fooChild.childAge = 6
$null = $fooCollection.fooChildrenList.Add([pscustomobject] $fooChild)

# Create and add another child.
$fooChild.childName = 'Rolf'; $fooChild.childAge = 10
$null = $fooCollection.fooChildrenList.Add([pscustomobject] $fooChild)

# Output the children
$fooCollection.fooChildrenList

^{注意 $null = ...，它抑制了 .Add() 方法调用中通常不需要的输出。}

以上结果：

childName childAge
--------- --------
Betsy            6
Rolf            10

一个稍微更晦涩的替代方案是坚持使用$fooChild作为[pscustomobject]实例并调用.psobject.Copy() 在上面创建一个克隆。

提供了一个更加模块化的解决方案，通过 辅助函数 根据需要创建新的自定义对象实例。 =28=]

最后，在 PSv5+ 中，您可以定义一个助手 class：

$fooCollection = [PSCustomObject] @{ fooChildrenList = New-Object Collections.ArrayList } 

# Define helper class
class FooChild {
  [string] $childName
  [int]    $childAge
}

# Create 1st child and add to list with [pscustomobject] cast
$null = $fooCollection.fooChildrenList.Add([FooChild] @{ childName = 'Betsy'; childAge = 6 })

# Create and add another child.
$null = $fooCollection.fooChildrenList.Add([FooChild] @{ childName = 'Rolf'; childAge = 10 })

# Output the children
$fooCollection.fooChildrenList

请注意如何通过简单地转换具有与 class 属性名称匹配的条目的哈希表来创建 [FooChild] 的实例。

如何将 System.Collections.ArrayList 添加到 PowerShell 自定义对象？

How do I add a System.Collections.ArrayList to a PowerShell custom object?

powershell

arraylist

pscustomobject