Retrieve Input from PowerShell TextBox - powershell

Question

I am working on a PowerShell application which should take a user id as input from a text box, then search ActiveDirectory and return three fields; however, every time I try to use it I receive the following error:
Get-ADUser : Cannot validate argument on parameter 'Identity'. The argument is null. Provide a valid value for the argument, and then try running the command again.
At C:\Path\cc-lookup-gui.ps1:40 char:21
+ $y = Get-ADUser $script:x -Properties cC
+ ~~~~~~~~~
+ CategoryInfo : InvalidData: (:) [Get-ADUser], ParameterBindingValidationException
+ FullyQualifiedErrorId : ParameterArgumentValidationError,Microsoft.ActiveDirectory.Management.Commands.GetADUser
Here is the code for my GUI and search function:
[System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")|Out-Null
[System.Reflection.Assembly]::LoadWithPartialName("System.Drawing")|Out-Null
$net = New-Object -ComObject Wscript.Network
$form = New-Object System.Windows.Forms.Form
$form.Width = 525
$form.Height = 350
$form.FormBorderStyle = [System.Windows.Forms.FormBorderStyle]::Fixed3D
$form.Text = "CC Lookup"
$form.MaximumSize = New-Object System.Drawing.Size(525,350)
$form.StartPosition = "centerscreen"
$form.KeyPreview = $true
$form.Add_KeyDown({if($_.KeyCode -eq "Enter"){$script:x=$input.Text;Search}})
$form.Add_KeyDown({if($_.KeyCode -eq "Escape"){$form.Close()}})
$input = new-object System.Windows.Forms.TextBox
$input.maxLength = 6
$input.Location = New-Object System.Drawing.Size(200,75)
add-type -assemblyName System.Windows.Forms
$label1 = New-Object System.Windows.Forms.Label
$label1.Location = New-Object System.Drawing.Size(200,25)
$label1.AutoSize = $true
$label1.Text = "Enter User ID:"
$Button1 = new-object System.Windows.Forms.Button
$Button1.Location = New-Object System.Drawing.Size(100,132)
$Button1.Size = New-Object System.Drawing.Size(80,20)
$Button1.Text = "Search"
$Button1.Add_Click({$script:x=$input.Text;Search})
$button2 = New-Object System.Windows.Forms.Button
$button2.Location = New-Object System.Drawing.Size(300,132)
$button2.Text = "Clear"
$button2.Add_Click({Clears})
function Search{
$y = Get-ADUser $script:x -Properties cC
$output = $y.samAccountName + '|' + $y.CN + '|' + $y.cC
Add-Type -AssemblyName System.Windows.Forms
$label = New-Object System.Windows.Forms.Label
$label.Text = $Output
$label.AutoSize = $true
$label.Location = New-Object System.Drawing.Size(200,100)
$form.controls.add($label)
}
function Clears{
$label.Text = $null
$input.Text = $null
}
$form.Controls.Add($label1)
$form.Controls.Add($button2)
$form.Controls.Add($input)
$form.Controls.Add($Button1)
$form.Add_Shown({$Form.Activate()})
$Form.ShowDialog()
$x = $input.Text
I have tried declaring the variable $x globally, directly calling $input.text for the search function, and converting $x into a string, all of which return this same error. I'm running PowerShell version 5.

Answer 1

$Input is a special variable name - see help about_Automatic_Variables - and won't do what you expect when you use it in your {} scriptblock, it will refer to scriptblock input (in this case, nothing), instead of your inputbox.
Try renaming it to something else.