[转载代码] [PowerShell每日技巧]PowerShell 4.0中的动态方法(20131105)

DAIC

Beginning with PowerShell 4.0, method names may come from variables. Here's a simple example:

$method = 'ToUpper'
'Hello'.$method()
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This can be useful when the method you want to use depends on something a script would need to figure out first.

function Convert-Text
{
  param
  (
    [Parameter(Mandatory)]
    $Text,
    [Switch]$ToUpper
  )

  if ($ToUpper)
  {
    $method = 'ToUpper'
  }
  else
  {
    $method = 'ToLower'
  }
  $text.$method()
}
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And this is how a user would call the function:

PS> Convert-Text 'Hello' hello PS> Convert-Text 'Hello' -ToUpper HELLO

By default, the function would convert text to lower case. When the switch parameter -ToUpper is specified, it converts the text to upper case instead. Thanks to dynamic methods, the function won't need separate code blocks for this.

http://powershell.com/cs/blogs/tips/archive/2013/11/05/dynamic-methods-in-powershell-4.aspx