我最初把这个问题复杂化了，现在我想简化一下:
是否有可能，更重要的是，Microsoft 正式支持我在 ValidateScript 部分中引用参数而不是被验证的参数？
这是我想做的:
function test
{
Param(
[switch]
$doThingA = $False,
[ValidateScript({
If( $doThingA -eq $True -and -not ( Test-Path $_ -PathType Leaf ) )
{
Write-Output $False
}
Write-Output $True
})]
[string]
$doThingA_FilePath
)
}
这是 powershell 的文档中关于 ValidateScript 参数的说明
When you use the ValidateScript attribute, the parameter value that is being validated is mapped to the $_ variable. You can use the $_ variable to refer to the parameter value in the script.
最佳答案
你让我很好奇，我进行了一些测试。您似乎可以在 ValidateScript 脚本 block 中访问其他参数的值，但前提是它们已经绑定(bind)。
即这完全取决于传递参数的顺序 - 您的 ValidateScript 参数应该在您想要在 ValidateScript 脚本 block 中访问的所有其他参数之后指定。
异常(exception)是:
在按属性名称绑定(bind)时切换参数 - 在我的测试中，它们总是返回false。- 如果您使用
ValidateScript的参数正在使用ValueFromPipeline，它似乎总是最后绑定(bind)，因此它可以访问所有其他参数。
附言这绝不是一项竞争性研究，所以请自行试验。
这是我的测试脚本:
function Test-ParamAccess
{
[CmdletBinding()]
Param
(
[Parameter(ValueFromPipelineByPropertyName = $true)]
[switch]$Alfa,
[Parameter(ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true)]
[ValidateScript({
'Output', [ordered]@{
Alfa = $Alfa
Bravo = $_
Charlie = $Charlie
} | Format-Table -Autosize | Out-String | Write-Warning
$true
})]
[string]$Bravo,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[string]$Charlie
)
}
$Cmdline = @(
"-Alfa -Bravo 'BRAVO' -Charlie 'CHARLIE'",
"-Alfa -Charlie 'CHARLIE' -Bravo 'BRAVO'",
"-Bravo 'BRAVO' -Alfa -Charlie 'CHARLIE'",
"-Bravo 'BRAVO' -Charlie 'CHARLIE' -Alfa",
"-Charlie 'CHARLIE' -Alfa -Bravo 'BRAVO'",
"-Charlie 'CHARLIE' -Bravo 'BRAVO' -Alfa"
)
$Hashtable = @(
'Alfa = $true ; Bravo = "BRAVO" ; Charlie = "CHARLIE" ;'
'Alfa = $true ; Charlie = "CHARLIE" ; Bravo = "BRAVO" ;'
'Bravo = "BRAVO" ; Alfa = $true ; Charlie = "CHARLIE" ;'
'Bravo = "BRAVO" ; Charlie = "CHARLIE" ; Alfa = $true ;'
'Charlie = "CHARLIE" ; Alfa = $true ; Bravo = "BRAVO" ;'
'Charlie = "CHARLIE" ; Bravo = "BRAVO" ; Alfa = $true ;'
) | ForEach-Object {
Invoke-Expression "[ordered]@{$_}"
}
$Pipeline = @(
"-Alfa -Charlie 'CHARLIE'",
"-Charlie 'CHARLIE' -Alfa"
)
$Separator = '=' * 80
$Separator, 'Arguments via commandline:', $Separator | Write-Host
$Cmdline | ForEach-Object {
Write-Host "Input: $_"
Invoke-Expression "Test-ParamAccess $_"
}
$Separator, 'Arguments via splatting:', $Separator | Write-Host
$Hashtable | ForEach-Object {
'Input:', ($_ | Out-String) | Write-Host
Test-ParamAccess @_
}
$Separator, 'Arguments via pipeline by property name:', $Separator | Write-Host
$Hashtable | ForEach-Object {
'Input:', ($_ | Out-String) | Write-Host
New-Object -TypeName PsCustomObject -Property $_ | Test-ParamAccess
}
$Separator, 'Arguments via pipeline by value:', $Separator | Write-Host
$Pipeline | ForEach-Object {
'Input:', ($_ | Out-String) | Write-Host
Invoke-Expression "'BRAVO' | Test-ParamAccess $_"
}
结果:
================================================================================
Arguments via commandline:
================================================================================
Input: -Alfa -Bravo 'BRAVO' -Charlie 'CHARLIE'
WARNING: Output
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie
Input: -Alfa -Charlie 'CHARLIE' -Bravo 'BRAVO'
WARNING: Output
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie CHARLIE
Input: -Bravo 'BRAVO' -Alfa -Charlie 'CHARLIE'
WARNING: Output
Name Value
---- -----
Alfa
Bravo BRAVO
Charlie
Input: -Bravo 'BRAVO' -Charlie 'CHARLIE' -Alfa
WARNING: Output
Name Value
---- -----
Alfa
Bravo BRAVO
Charlie
Input: -Charlie 'CHARLIE' -Alfa -Bravo 'BRAVO'
WARNING: Output
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie CHARLIE
Input: -Charlie 'CHARLIE' -Bravo 'BRAVO' -Alfa
WARNING: Output
Name Value
---- -----
Alfa
Bravo BRAVO
Charlie CHARLIE
================================================================================
Arguments via splatting:
================================================================================
Input:
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie CHARLIE
WARNING: Output
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie
Input:
Name Value
---- -----
Alfa True
Charlie CHARLIE
Bravo BRAVO
WARNING: Output
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie CHARLIE
Input:
Name Value
---- -----
Bravo BRAVO
Alfa True
Charlie CHARLIE
WARNING: Output
Name Value
---- -----
Alfa
Bravo BRAVO
Charlie
Input:
Name Value
---- -----
Bravo BRAVO
Charlie CHARLIE
Alfa True
WARNING: Output
Name Value
---- -----
Alfa
Bravo BRAVO
Charlie
Input:
Name Value
---- -----
Charlie CHARLIE
Alfa True
Bravo BRAVO
WARNING: Output
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie CHARLIE
Input:
Name Value
---- -----
Charlie CHARLIE
Bravo BRAVO
Alfa True
WARNING: Output
Name Value
---- -----
Alfa
Bravo BRAVO
Charlie CHARLIE
================================================================================
Arguments via pipeline by property name:
================================================================================
Input:
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie CHARLIE
WARNING: Output
Name Value
---- -----
Alfa False
Bravo BRAVO
Charlie CHARLIE
Input:
Name Value
---- -----
Alfa True
Charlie CHARLIE
Bravo BRAVO
WARNING: Output
Name Value
---- -----
Alfa False
Bravo BRAVO
Charlie CHARLIE
Input:
Name Value
---- -----
Bravo BRAVO
Alfa True
Charlie CHARLIE
WARNING: Output
Name Value
---- -----
Alfa False
Bravo BRAVO
Charlie CHARLIE
Input:
Name Value
---- -----
Bravo BRAVO
Charlie CHARLIE
Alfa True
WARNING: Output
Name Value
---- -----
Alfa False
Bravo BRAVO
Charlie CHARLIE
Input:
Name Value
---- -----
Charlie CHARLIE
Alfa True
Bravo BRAVO
WARNING: Output
Name Value
---- -----
Alfa False
Bravo BRAVO
Charlie CHARLIE
Input:
Name Value
---- -----
Charlie CHARLIE
Bravo BRAVO
Alfa True
WARNING: Output
Name Value
---- -----
Alfa False
Bravo BRAVO
Charlie CHARLIE
================================================================================
Arguments via pipeline by value:
================================================================================
Input:
-Alfa -Charlie 'CHARLIE'
WARNING: Output
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie CHARLIE
Input:
-Charlie 'CHARLIE' -Alfa
WARNING: Output
Name Value
---- -----
Alfa True
Bravo BRAVO
Charlie CHARLIE
关于validation - 引用 Powershell 的 ValidateScript 中的其他参数，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36253299/