Powershell的“特殊"功能开关参数 [英] Powershell "special" switch parameter

问题描述

我在下面具有Powershell功能

I have the powershell function below

Function Test
{
    Param
    (               
        [Parameter()]
        [string]$Text = "default text"
    )

    Write-Host "Text : $($Text)"
}

我希望能够像下面这样调用此函数:

And I would like to be able to call this function like below :

测试-文本:应在主机上显示默认文本

Test -Text : should display the default text on the host

测试-文本另一个文本" :应在主机上显示提供的文本

Test -Text "another text" : should display the provided text on the host

我的问题是，powershell中不允许使用第一种语法.

My issue is that the first syntax is not allowed in powershell ..

关于如何实现此目标的任何想法? 我想要一种开关"参数，该参数可以采用布尔值以外的其他值.

Any ideas of how I can achieve this goal ? I would like a kind of 'switch' parameter that can take values other than boolean.

谢谢

推荐答案

您遇到的问题是参数绑定. PowerShell正在看到[string] $Text并期望有一个值.您可以这样解决:

The problem you're running into is with parameter binding. PowerShell is seeing [string] $Text and expecting a value. You can work around this like so:

function Test {
    param(
        [switch]
        $Text,

        [Parameter(
            DontShow = $true,
            ValueFromRemainingArguments = $true
        )]
        [string]
        $value
    )

    if ($Text.IsPresent -and [string]::IsNullOrWhiteSpace($value)) {
        Write-Host 'Text : <default text here>'
    }
    elseif ($Text.IsPresent) {
        Write-Host "Text : $value"
    }
}

注意:这是一个骇人听闻的解决方案，当不传递参数时，您应该使用默认值.

Note: this is a hacky solution and you should just have a default when parameters aren't passed.

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