powershell - 使用Add-Member从数组创建对象

Question

我正在使用脚本来创建具有以下特定值的新对象。这在$ Names返回单个字符串值的情况下起作用，但是当存在数组时并且在打印$ newobj之前，将得到以下错误。当我为$ Names添加foreach语句时，试图找出导致错误的原因。还要注意，对于$ names数组中的两个值John，Jake，$ x的值与“London”相同。

在当前输出中，StudentName两次都打印为“John”，当我使用参数–Force时，StudentName的值两次都为“Jake”。我需要在输出中将这些值分开，有人可以帮助我吗？请？

Add-Member : Cannot add a member with the name "StudentName" because a member with that name already exists. To overwrite the
member anyway, add the Force parameter to your command.
At E:\test.ps1:93 char:14
+             $newobj | Add-Member -MemberType NoteProperty -Name StudentName -Value $_

脚本:

# $DCNames is an array

Foreach($x in $DCNames){
        $newobj = New-Object psobject
        $newobj | Add-Member -MemberType NoteProperty -Name DC -Value $x

        ######  $Names in most cases is a single string or it could be also an array. For example: it could be a value Adam or {John Jake….} and so I would need to Add each member in $Names as StudentName object below.
        $Names =@()
        $Names = $List | Where-Object{$_.Name -eq $x} | Select -ExpandProperty Name

        $Names | foreach {
            $newobj | Add-Member -MemberType NoteProperty -Name StudentName -Value $_   
            # $ClassName is a single string
            $newobj | Add-Member -MemberType NoteProperty -Name Class -Value $ClassName
            $newobj
            }

电流输出:

Name: Vegas
StudentName: Adam
Class: 10

Name: London
StudentName: John
Class: 12

Name: London
StudentName: John (the script should take the second value “Jake” here from $Names array, but is not happening for some reason)
Class: 11

Answer 1

您仅创建1个对象，然后尝试覆盖同一对象上的StudentName。改为这样做:

Foreach($x in $DCNames){
    ######  $Names in most cases is a single string or it could be also an array. For example: it could be a value Adam or {John Jake….} and so I would need to Add each member in $Names as StudentName object below.
    $Names = @()
    $Names = $List | Where-Object{$_.Name -eq $x} | Select -ExpandProperty Name

    $Names | foreach {
        $newobj = New-Object psobject
        $newobj | Add-Member -MemberType NoteProperty -Name DC -Value $x
        $newobj | Add-Member -MemberType NoteProperty -Name StudentName -Value $_ 
        $newobj | Add-Member -MemberType NoteProperty -Name Class -Value $ClassName
        $newobj
    }
}

用管道传输到 Add-Member可能会很慢，您可能想改用 New-Object -Property @{}:

Foreach($x in $DCNames){
    ######  $Names in most cases is a single string or it could be also an array. For example: it could be a value Adam or {John Jake….} and so I would need to Add each member in $Names as StudentName object below.
    $Names = @()
    $Names = $List | Where-Object{$_.Name -eq $x} | Select -ExpandProperty Name

    $Names | foreach {
        $newobj = New-Object psobject -Property @{
            DC = $x
            StudentName = $_ 
            Class = $ClassName
        }
    }
}