How do I update a variable in a variable in powershell?

Question

I'm making a menu system for a script I have where I can change the values I need to by using the menu or by passing them as arguments to the script. One of the annoyances I have at the moment is after entering a new value when the menu refreshes, the variable in the menu text does not update to the new values.

      $global:drive="C:"

      $title = "Setup 

      "
           $message = "The default variables are:
            VARIABLES TO CHANGE

            1. The Drive Location: $global:drive <<<--- This is the variable that does not update after I change it when I run the script.
       "

      $one = New-Object System.Management.Automation.Host.ChoiceDescription "&1 Drive", "The Drive Location:"

      $options = [System.Management.Automation.Host.ChoiceDescription[]]($one)

     :OuterLoop do 
{ 
    for ($i = 1; )
    {

      $result =  $host.ui.PromptForChoice($title, $message, $options, 1) 

    switch ($result)
        {
            0 {$global:drive = Read-Host "Drive is $global:drive .Set the  Drive Location";
                "The Drive is now: $global:drive";
                break;}

          }

                }
}

 while ($y -ne 100)

Initially I did not set the variable to to global but read on here that that might help. It did not but it did not hurt either. I also tried setting it to script too. The variable does change, so this is cosmetic more than anything.

Thanks

Nick · Accepted Answer · 2012-08-21 17:32:22Z

1

I ran your code, but mine changes in the menu. The only thing I did was comment out your first $global:drive="C:". If this is always at the top of the script, then $global:drive will always display C:.

You can use the following code to check for the existance of a variable, then assign the value if it doesn't already exist:

if $(!(Get-Variable -Name Drive -Scope global -ErrorAction SilentlyContinue)) { $global:drive="C:" }

If the global variable Drive exists, it will do nothing. If it doesn't exist, $global:drive will be set to C:. Hope this helps.

Edit after @Norm comment:

The reason your message isn't updating, is because the $title is set outside of the loop. Because $Title is already defined, it doesn't need to change every time the loop runs. Simply move the declaration for $Title inside the loop before the line $result = $host.ui.PromptForChoice($title, $message, $options, 1). This should fix the problem you are having.

Edit2: I'm sorry, it's $message that needs moved, not $title

edited Aug 21, 2012 at 17:32

answered Aug 21, 2012 at 14:52

Nick

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3 Comments

Norm Over a year ago

Thanks Nick. The code I gave was inaccurate as is part if a larger set and I had to hack it down a little to get to the point. Doing so I left off the while loop. If you run that again, you should see what I mean. You brought up a great point though. Thanks

Norm Over a year ago

OH MAN THAT WAS SOOOO OBVIOUS. Thanks Nick. I just keep telling myself... DUH1 :)

Nick Over a year ago

No problem, we've all done the same thing at some point or another :)

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