powershell - 防止胁迫

Question

假设:

Function Invoke-Foo {
  Param(
    [string[]]$Ids
  )
  Foreach ($Id in $Ids) {    
    Write-Host $Id
  }
}

如果我这样做:

PS> Invoke-Foo -ids '0000','0001'
0000
0001

如果我这样做:

PS> Invoke-Foo -ids 0000,0001
0
1

在第二种情况下，除了使它们成为显式字符串(第一种情况)之外，还有其他方法可以防止强制吗？

Answer 1

不，不幸的是没有。

从 about_Parsing 帮助文件中:

When processing a command, the Windows PowerShell parser operates
in expression mode or in argument mode: 

    - In expression mode, character string values must be contained in
      quotation marks. Numbers not enclosed in quotation marks are treated
      as numerical values (rather than as a series of characters). 

    - In argument mode, each value is treated as an expandable string 
      unless it begins with one of the following special characters: dollar
      sign ($), at sign (@), single quotation mark ('), double quotation
      mark ("), or an opening parenthesis (().

因此，解析器在将任何内容传递给函数之前先评估 0001。我们可以使用 0001方法测试将 ExpandString()视为“可扩展字符串”的效果:

PS C:\> $ExecutionContext.InvokeCommand.ExpandString(0001)
1