PowerShell module - pass a parameter while importing module

Question

In the below sample module file, is there a way to pass the myvar value while importing the module.

For example,

import-module -name .\test.psm1 -?? pass a parameter? e.g value of myvar

#test.psm1
$script:myvar = "hi"
function Show-MyVar {Write-Host $script:myvar}
function Set-MyVar ($Value) {$script:myvar = $Value}
#end test.psm1

(This snippet was copied from another question.)

Answer 1

This worked for me:

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

You should use a param block 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.

Reference

Answer 2

The -ArgumentList parameter of Import-Module unfortunately does not accept a [hashtable] or [psobject] or something. A list with fixed postitions is way too static for my liking so I prefer to use a single [hashtable]-argument which has to be "manually dispatched" like this:

param( [parameter(Mandatory=$false)][hashtable]$passedVariables )
# this module uses the following variables that need to be set and passed as [hashtable]:
#  BeQuiet, URL, LotsaMore...
$passedVariables.GetEnumerator() |
  ForEach-Object { Set-Variable -Name $_.Key -Value $_.Value }
...

The importing module or script does something like this:

...
# variables have been defined at this point
$variablesToPass = @{}
'BeQuiet,URL,LotsaMore' -split ',' |
    ForEach-Object { $variablesToPass[$_] = Get-Variable $_ -ValueOnly }
Import-Module TheModule -ArgumentList $variablesToPass

The above code uses the same names in both modules but you could of course easily map the variable names of the importing script arbitrarily to the names that are used in the imported module.