Loading (import) a module with arguments

You can use the –ArgumentList parameter of the import-module cmdlet to pass arguments when loading a module.

You should use a param bloc in your module to define your parameters :

param(
    [parameter(Position=0,Mandatory=$false)][boolean]$BeQuiet=$true,
    [parameter(Position=1,Mandatory=$false)][string]$URL
)

Then call the import-module cmdlet like this :

import-module .\myModule.psm1 -ArgumentList $True,'http://www.microsoft.com'

As may have already noticed, you can only supply values (no names) to –ArgumentList. So you should define you parameters carefully with the position argument.

How to add –whatif support to a function

 

Function Get-HelloWorld {
    [CmdletBinding(SupportsShouldProcess=$true,ConfirmImpact="Low")]
    param()
    $message="Hello world"
    if ($PSCmdlet.ShouldProcess($message,"Write-host")) {
        write-host $message
    }
  }

Get-HelloWorld -whatif will produce :

What if: Performing operation "Write-host" on Target "Hello world".

As a bonus, you will also be able to use the -confirm and –verbose parameter

How to use ParameterSets in a CmdLet ?

Here’s a quick sample :

function test-param 
{ 
[CmdletBinding(DefaultParametersetName="p2")] 
param( 
[Parameter(ParameterSetName="p1",Position=0)] 
[String] 
$d, 

[Parameter(ParameterSetName="p2", Position=0)] 
[String]$i 
) 
    switch ($PsCmdlet.ParameterSetName) 
    { 
    "p1"  { Write-Host ([DateTime]$d); break} 
    "p2"  { Write-Host ([INT]$i); break} 
    } 
}

For the complete explanation : PowerShell V2: ParameterSets From Jeffrey Snover [MSFT] @ Windows PowerShell Blog