Question

我想知道这是否可以在参数级别而不是代码中完成：我有2个参数：$ School和$ Class

Get-Students -School SchooName # Will give me all Students name in all classes in that School
Get-Students -Class ClassName  # Will give me all Students name in that Class across all schools
Get-Students                   # Should return parameter level error.

我尝试使用以下内容：

function Get-Students{
param(
    [parameter(ParameterSetName="School no null")]
    [ValidateNotNullOrEmpty()]
    [string]$School,
    [parameter(ParameterSetName="School no null")]
    [AllowNull()]
    [string]$Class,
    [parameter(ParameterSetName="Class no null")]
    [AllowNull()]
    [string]$School,
    [parameter(ParameterSetName="Class no null")]
    [ValidateNotNullOrEmpty()]
    [string]$Class
)
}

但它并没有以这种方式运作......

希望我正确解释了这一点。或者，如果没有办法只能在代码内部的参数中执行此操作？

由于河

Answer 1

您可以在代码中测试它们，而不是尝试将此检查填入参数集。

if ($School -eq $null -and $Class -eq $null) {throw "School and Class must not be null together!"}

Answer 2

<强>更新即可。以下评论代码段基于Add a parameter to multiple Parameter Sets文章。允许同时提供-Class或-School参数或两者。

function Get-Students{
param(
    [parameter(Mandatory=$false)][switch]$SomeThing, # any type instead of [switch]
    # ↑↑↑ parameter(s) in all Parameter Sets

    [parameter(Mandatory=$true,  ParameterSetName="School No Null")]
    [parameter(Mandatory=$true,  ParameterSetName="Class And School")]
    [ValidateNotNullOrEmpty()]
    [string]$School,

    [parameter(Mandatory=$true,  ParameterSetName="Class No Null")]
    [parameter(Mandatory=$true,  ParameterSetName="Class And School")]
    [ValidateNotNullOrEmpty()]
    [string]$Class
)
    Write-Host $PsCmdlet.ParameterSetName -ForegroundColor Cyan
    switch ($PsCmdlet.ParameterSetName) 
    { 
        "School No Null"   { "$School/*,$($SomeThing.IsPresent)"; break} 
        "Class No Null"    { "*/$Class,$($SomeThing.IsPresent)";  break}
        "Class And School" { "$School/$Class,$($SomeThing.IsPresent)";  break}
    }
}
Get-Students -Class "A"
Get-Students -School "West" -SomeThing
Get-Students -Class "A" -School "West"

### errors raised:
#   Get-Students
### Parameter set cannot be resolved using the specified named parameters.
### + FullyQualifiedErrorId : AmbiguousParameterSet,Get-Students
#   Get-Students -Class ""
#   Get-Students -School ""
### Cannot validate argument on parameter '…'. The argument is null or empty.
### + FullyQualifiedErrorId : ParameterArgumentValidationError,Get-Students

原始回答（基于来自 PowerShell团队博客的PowerShell V2: ParameterSets文章和MSDN help article上的的代码段不允许< / strong>同时提供 -Class和-School参数：

function Get-Students{ param( [parameter(Mandatory=$true, ParameterSetName="School No Null")][ValidateNotNullOrEmpty()] [parameter(Mandatory=$false, ParameterSetName="Class No Null")] #[AllowNull()] [string]$School, [parameter(Mandatory=$true, ParameterSetName="Class No Null")] [ValidateNotNullOrEmpty()] [parameter(Mandatory=$false, ParameterSetName="School No Null")]#[AllowNull()] [string]$Class ) Write-Host $PsCmdlet.ParameterSetName -ForegroundColor Cyan switch ($PsCmdlet.ParameterSetName) { "School No Null" { $School; break} "Class No Null" { $Class; break} } } ### valid calls: Get-Students -Class "A" Get-Students -School "West" ### errors raised: ### Parameter set cannot be resolved using the specified named parameters. # Get-Students # Get-Students -Class "A" -School "West" ### The argument is null or empty. # Get-Students -Class "" # Get-Students -School ""

PowerShell中的两个参数可以为null，但不能为null

2 个答案: