[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:

1. $method = 'ToUpper'
   
2. 'Hello'.$method()

复制代码

This can be useful when the method you want to use depends on something a script would need to figure out first.

1. function Convert-Text
   
2. {
   
3.   param
   
4.   (
   
5.     [Parameter(Mandatory)]
   
6.     $Text,
   
7.     [Switch]$ToUpper
   
8.   )
   
9. 
   
10.   if ($ToUpper)
    
11.   {
    
12.     $method = 'ToUpper'
    
13.   }
    
14.   else
    
15.   {
    
16.     $method = 'ToLower'
    
17.   }
    
18.   $text.$method()
    
19. }

复制代码

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