使用自定义PowerShell定义的类型进行参数类型规范

Question

我使用New-Object定义自定义PowerShell类型.我希望参数是我定义的类型,是否可以以声明方式指定此类型？下面的代码给出了错误:"无法找到类型[BuildActionContext]:确保加载包含此类型的程序集."

我们可以指定声明类型,还是应该只测试指定对象的类型？

不工作的代码:

$buildActionContext = New-Object -TypeName PSObject -Property @{
# Given properties
BuildAction = "Build"; 
}
$buildActionContext.PSObject.TypeNames.Insert(0, 'BuildActionContext')

function DoSomethingWithBuildActionContext
{
[CmdletBinding()]
param
(
    [Parameter(Mandatory=$true)][BuildActionContext]$Context
)

Write-Host "Build action: $($Context.BuildAction)"
}

DoSomethingWithBuildActionContext -Context $buildActionContext

工作代码,但可以不同的方式完成:

$buildActionContext = New-Object -TypeName PSObject -Property @{
        # Given properties
        BuildAction = "Build"; 
    }
    $buildActionContext.PSObject.TypeNames.Insert(0, 'BuildActionContext')

function DoSomethingWithBuildActionContext
{
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory=$true)]$Context
    )

    if ($Context.PSObject.TypeNames[0] -ne 'BuildActionContext')
    {
        throw "Context parameter not of type 'BuildActionContext'"
    }

    Write-Host "Build action: $($Context.BuildAction)"
}

DoSomethingWithBuildActionContext -Context $buildActionContext
DoSomethingWithBuildActionContext -Context "Hello world"

注意:第二次调用会给出异常消息.

Answer 1

我希望只有真正的.NET类型可用于指定参数类型.根据Essential PowerShell:命名自定义对象类型,自定义类型名称主要用于格式化.

您可以通过ValidateScript属性手动检查类型名称:

function DoSomethingWithBuildActionContext { 
  param(
    [Parameter()]
    [ValidateScript({ $_.PSObject.TypeNames[0] -eq 'BuildActionContext' })]
    $context
  )
  Write-Host "Build action: $($Context.BuildAction)"
}