Passing input variable from PowerShell form to cmdlet argument results in blank data

Question

I'm trying to take an inputted text string like WIN from a PowerShell form and find all computers having WIN as the first three letters of their computer name.

To do this I built off of a Microsoft Technet example and only very slightly modified the code to take the inputted text string and save it as variable $global:x. I pass that variable ($global:x) into a filter in the last line of code which outputs to a file but the output file is blank. I've done some googling, and changed the variable from $x to $global:x but that didn't work.

File is still blank. My only changes to the TechNet code example was changing the variable from $x to $global:x and add the filter at the end; the filter is the very last line in the code and is supposed to pipe the variable results into the output file.

The entire code is below.

[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing") 
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms") 

$objForm = New-Object System.Windows.Forms.Form 
$objForm.Text = "FindSimiliarComputers"
$objForm.Size = New-Object System.Drawing.Size(300,200) 
$objForm.StartPosition = "CenterScreen"

$objForm.KeyPreview = $True
$objForm.Add_KeyDown({if ($_.KeyCode -eq "Enter") 
    {$global:x=$objTextBox.Text;$objForm.Close()}})
$objForm.Add_KeyDown({if ($_.KeyCode -eq "Escape") 
    {$objForm.Close()}})

$OKButton = New-Object System.Windows.Forms.Button
$OKButton.Location = New-Object System.Drawing.Size(75,120)
$OKButton.Size = New-Object System.Drawing.Size(75,23)
$OKButton.Text = "OK"
$OKButton.Add_Click({$global:x=$objTextBox.Text;$objForm.Close()})
$objForm.Controls.Add($OKButton)

$CancelButton = New-Object System.Windows.Forms.Button
$CancelButton.Location = New-Object System.Drawing.Size(150,120)
$CancelButton.Size = New-Object System.Drawing.Size(75,23)
$CancelButton.Text = "Cancel"
$CancelButton.Add_Click({$objForm.Close()})
$objForm.Controls.Add($CancelButton)

$objLabel = New-Object System.Windows.Forms.Label
$objLabel.Location = New-Object System.Drawing.Size(10,20) 
$objLabel.Size = New-Object System.Drawing.Size(280,20) 
$objLabel.Text = "Please enter the partial computer name"
$objForm.Controls.Add($objLabel) 

$objTextBox = New-Object System.Windows.Forms.TextBox 
$objTextBox.Location = New-Object System.Drawing.Size(10,40) 
$objTextBox.Size = New-Object System.Drawing.Size(260,20) 
$objForm.Controls.Add($objTextBox) 

$objForm.Topmost = $True

$objForm.Add_Shown({$objForm.Activate()})
[void] $objForm.ShowDialog()

Get-ADComputer -filter {name -like "$global:x*" -and Enabled -eq "true" } | Select -expand Name | out-file C:\Users\Admin1\Desktop\computers.txt 

Answer 1

Your Get-ADComputer filter syntax is broken

Change it to :

Get-ADComputer -filter "name -like '$global:x*' -and Enabled -eq 'true'" | Select -expand Name | out-file C:\Users\Admin1\Desktop\computers.txt 

And your script will work.

The article you followed is very out of date - there is discussion of what's wrong with it, and new updated examples from 2014 on The Scripting Guys' blog here