无法在 Validateset 中使用预定义数组 - Powershell [英] Couldn't use predefined array inside Validateset - Powershell

问题描述

我正在寻找一种方法来制作一个 cmdlet，该 cmdlet 接收参数并在输入时提示从预定义的选项数组中完成的建议.

I'm looking for a way to make a cmdlet which receives parameter and while typing, it prompts suggestions for completion from a predefined array of options.

我正在尝试这样的事情:

I was trying something like this:

$vf = @('Veg', 'Fruit')
function Test-ArgumentCompleter {
  [CmdletBinding()]
    param (
          [Parameter(Mandatory=$true)]
          [ValidateSet($vf)]
          $Arg
    )
}

预期的结果应该是:
编写Test-ArgumentCompleter F"时，单击 tub 按钮后，F 自动完成为 Fruit.

The expected result should be:
When writing 'Test-ArgumentCompleter F', after clicking the tub button, the F autocompleted to Fruit.

推荐答案

• PowerShell 通常要求属性是 literals(例如 'Veg')或 constants(例如 $true).

  • PowerShell generally requires that attribute properties be literals (e.g., 'Veg') or constants (e.g., $true).

    动态功能需要使用 脚本块(本身指定为文字、{ ... })，或者在特定情况下，输入文字.

    Dynamic functionality requires use of a script block (itself specified as a literal, { ... }) or, in specific cases, a type literal.

    但是，[ValidateSet()] 属性只接受字符串数组(按需定义)文字或 - 在 PowerShell (Core) v6 及更高版本 - a 输入文字(见下文).

    However, the [ValidateSet()] attribute only accepts an array of string(ified-on-demand) literals or - in PowerShell (Core) v6 and above - a type literal (see below).

    更新:

    • 如果您使用的是 PowerShell(核心)v6+，有一个更简单的解决方案，它基于定义一个自定义class，实现了System.Management.Automation.IValidateSetValuesGenerator interface - 见第二个解决方案在 iRon 的有用回答中.

    • If you're using PowerShell (Core) v6+, there's a simpler solution based on defining a custom class that implements the System.Management.Automation.IValidateSetValuesGenerator interface - see the 2nd solution in iRon's helpful answer.

    即使在 Windows PowerShell 中，也可以使用更简单的解决方案如果您的验证值可以定义为 enum 类型 - 见Mathias R. Jessen 的有用回答.

    Even in Windows PowerShell a simpler solution is possible if your validation values can be defined as an enum type - see Mathias R. Jessen's helpful answer.

    要获得基于非文字值数组的所需功能，您需要结合其他两个属性:

    To get the desired functionality based on a non-literal array of values, you need to combine two other attributes:

    • [ArgumentCompleter()] 用于动态制表符补全.

    • [ArgumentCompleter()] for dynamic tab-completion.

    [ValidateScript()] 用于确保在命令提交时参数确实是数组中的一个值，使用 脚本块.

    # The array to use for tab-completion and validation.
    [string[]] $vf = 'Veg', 'Fruit'
    
    function Test-ArgumentCompleter {
      [CmdletBinding()]
      param(
        [Parameter(Mandatory)]
        # Tab-complete based on array $vf
        [ArgumentCompleter(
          { param($cmd, $param, $wordToComplete) $vf -like "$wordToComplete*" }
        )]
        # Validate based on array $vf.
        # NOTE: If validation fails, the (default) error message is unhelpful.
        #       Unfortunately, this cannot be helped in *Windows PowerShell*, but in
        #       PowerShell (Core) 7+, you can add an `ErrorMessage` property:
        #         [ValidateScript({ $_ -in $vf }, ErrorMessage = 'Unknown value: {0}')]
        [ValidateScript( { $_ -in $vf })]
        $Arg
      )
    
      "Arg passed: $Arg"
    }
    

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