PowerShell Coding Trick

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Hey Y’all,

I was doing some investigating in PowerShell the other day and found out that you can call
another .ps1 program from your current .ps1 running program and then use both functions
and variables declared in the initial program.

Here’s a couple of test files you can mess with if you are so inclined.

Test-CallingExternalCode.ps1:

#---  Test-CallingExternalCode.ps1 ---

#----- Setup for User Messaging --------------------
Add-Type -AssemblyName System.Windows.Forms  

$MsgBox  = [Windows.Forms.MessageBox]
$Buttons = [Windows.Forms.MessageBoxButtons]
#Values: OK, OkCancel, AbortRetryIgnore, YesNo, 
#        YesNoCancel, RetryCancel

$Icon    = [Windows.Forms.MessageBoxIcon]
#Values: None Question, [Stop | Hand], 
#        [Warning | Exclamation], [Information | Asterisk]

$top = 
 new-Object System.Windows.Forms.Form -property @{Topmost=$true}
$StatusMsg = {
  $MsgBox::Show($top,$Message,$MBTitle,$Buttons,$Icon)}

#---------- End User Messaging Setup --------------------------

Function Hello { 
   $Message = "I'm Function Hello called from " +
              "Test-CalledExternalCode.ps1"
   $MBTitle = "Function Hello:"
   $Buttons = "Ok"
   $Icon    = "Information"
   $Null    = & $StatusMsg
 } #Used in called script

Clear-Host

If (Test-Path -Path "$PsScriptRoot\Test-CalledExternalCode.ps1") {

 #--- Code for retrieving answer from called script  ---#
 
 $Answer = & ($PsScriptRoot + "\Test-CalledExternalCode.ps1")

 "The Answer was: $Answer"

<#--- Code when not retrieving answer from called script --- $Null = & ($PsScriptRoot + "\Test-CalledExternalCode.ps1") #>

} #End Test-CallingExternalCode.ps1

Test-CalledExternalCode.ps1:

#---  Test-CalledExternalCode.ps1  ---

<#+---------------------------------------------------------+ | Note: This program uses the Message Box code setup from | | the calling script to write its message! | +---------------------------------------------------------+ #>

Hello   #--- Function declared in calling script
#---  Test-CalledExternalCode.ps1  ---

#--- Variables declared in calling script ---

$Message = "I'm Function Set-Cleanup"
$MBTitle = "Program Running:"
$Buttons = "YesNo"
$Icon    = "Information"

#--- When retruning the Msg result to the calling script ---

& $StatusMsg  #Note: &StatusMsg defined in calling script!

<#--- When not returning a value to the calling script --- $Null = & $StatusMsg #>

#--- End: Test-CalledExternalCode.ps1  ---

Note: Both programs must reside in the same directory, there might be ways around this but I haven’t worked this out yet.
If the called program doesn’t exist the calling program will just ignore it and continue on. I found this useful as it allows end users to add their own code, if desired, to a program I’ve written as long as they name it properly.

Hope you find this as interesting as I did.

May the Forces of good computing be with you!

RG

PowerShell & VBA Rule!
Computer Specs

1 user thanked author for this post.

Rick Corbett

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