条件 PowerShell 参数 [英] Conditional PowerShell parameters

问题描述

有没有办法根据 PowerShell 函数中的某些条件(例如，如果其中一个参数不存在或为假)强制某些参数?

Is there a way to have some of the parameters mandatory based on some condition (for example, if one of the parameters is absent or false) in a PowerShell function?

我的想法是能够以两种方式调用函数.一个具体的例子是一个从 SharePoint 获取列表的函数 - 我应该能够使用列表的相对 URL(一个且唯一的参数)或使用 Web URL 和列表显示名称(两个参数，都是必需的，但是仅当未使用列表相对 URL 时).

My idea is to be able to call a function in two ways. A concrete example is a function that gets a list from SharePoint - I should be able to call it with relative URL of the list (one and only parameter) OR with a web URL and a list display name (two parameters, both mandatory, but only if list relative URL is not used).

推荐答案

正如 Christian 所指出的，这可以通过 ParameterSetNames 来完成.看看这个例子:

As Christian indicated, this can be accomplished via ParameterSetNames. Take a look at this example:

function Get-MySPWeb {
    [CmdletBinding(DefaultParameterSetName="set1")]
    param (
        [parameter(ParameterSetName="set1")] $RelativeUrl,
        [parameter(ParameterSetName="set2")] $WebUrl,
        [parameter(ParameterSetName="set2", Mandatory=$true)] $DisplayName
    )
    Write-Host ("Parameter set in action: " + $PSCmdlet.ParameterSetName)
    Write-Host ("RelativeUrl: " + $RelativeUrl)
    Write-Host ("WebUrl: " + $WebUrl)
    Write-Host ("DisplayName: " + $DisplayName)
}

如果您使用 -RelativeUrl Foo 运行它，它将绑定到set1".如果你不带任何参数调用这个函数，它也会绑定到set1".

If you run it with -RelativeUrl Foo it will bind to "set1". If you call this function without any parameters it will also bind to "set1".

(注意 - 当 PowerShell v3(带有 Windows 8 消费者预览版)中没有提供参数时，它将绑定到set1"，但是它会在 PowerShell v2 中错误绑定，除非您将 [CmdletBinding(DefaultParameterSetName="set1")] 添加到参数块.感谢 @x0n 提供 DefaultParameterSetName 提示！)

(Note - when no parameters are provided in PowerShell v3 (with Windows 8 consumer preview) it will bind to "set1", however it will error binding in PowerShell v2 unless you add [CmdletBinding(DefaultParameterSetName="set1")] to the parameter block. Thanks @x0n for the DefaultParameterSetName tip!)

如果您尝试使用来自两个集合的参数值运行它，则会出现错误.

If you try to run it with a parameter value from both sets you will get an error.

如果您使用 -WebUrl Bar 运行它，它会提示您输入 DisplayName 的参数值，因为它是必需参数.

If you run it with -WebUrl Bar it will prompt you for a parameter value for DisplayName, because it's a mandatory parameter.

这篇关于条件 PowerShell 参数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！