为什么powershell会重新排列我的输出？

Question

我CustomObject在我的函数中构建了以下内容

    New-Object -Type PSCustomObject -Property @{
        Computername      = $_
        PowerShellVersion = $result[0]
        dotNetVersion     = $result[1]
        sqlnacli          = $result[2]
        redistributable   = $result[3]
    }

但输出是这样的:

PowerShellVersion Computername redistributable sqlnacli dotNetVersion
----------------- ------------ --------------- -------- -------------
3+ OK             SERVERNAME     NOT OK          NOT OK   NOT OK    

为什么PowerShell重新排列我的对象的顺序,我怎么能强迫它采取我想要的顺序？

Answer 1

根据定义,不按顺序排列哈希表.如果您有PowerShell v3.0或更高版本,则可以使用[Ordered]哈希表的属性:

New-Object PSCustomObject -Property ([Ordered] @{
  Computername      = $_
  PowerShellVersion = $result[0]
  dotNetVersion     = $result[1]
  sqlnacli          = $result[2]
  redistributable   = $result[3]
})

在PowerShell v3 +中,您还可以使用[PSCustomObject]类型加速器:

[PSCustomObject] @{
  Computername      = $_
  PowerShellVersion = $result[0]
  dotNetVersion     = $result[1]
  sqlnacli          = $result[2]
  redistributable   = $result[3]
}

如果您需要PowerShell版本2兼容性,那么您可以使用

New-Object PSObject -Property @{
  Computername      = $_
  PowerShellVersion = $result[0]
  dotNetVersion     = $result[1]
  sqlnacli          = $result[2]
  redistributable   = $result[3]
} | Select-Object Computername,PowerShellVersion,dotNetVersion,sqlnacli,redistributable

此方法的缺点是,如果添加属性,则必须记住将其添加到Select-Object.

替代PowerShell v2或更早版本是输出一些东西(例如,空字符串),然后用于Select-Object创建您想要的自定义属性:

$obj = $_
"" | Select-Object `
  @{Name = "Computername";      Expression = {$obj}},
  @{Name = "PowerShellVersion"; Expression = {$result[0]}},
  @{Name = "dotNetVersion";     Expression = {$result[1]}},
  @{Name = "sqlnacli";          Expression = {$result[2]}},
  @{Name = "redistributable";   Expression = {$result[3]}}

这里唯一(次要)的缺点是$_in Select-Object指的是从中选择属性的前一个对象(因此$obj = $_作为第一行,保留值).