Checkboxes handling with errors

I have some problem with Add_checkStateChanged method (checkbox object) in Powershell. I have some dynamic form where I'm creating group of checkboxes. I do this by using something like that:

New-Variable -Name "checkBox_${item}_${i}" -Value (New-Object System.Windows.Forms.Checkbox)

Also I check activity on this obcjects by:

$checkboxes = (Get-Variable checkBox_*_*)
$checkboxes | ForEach {
    $_.Value.Add_CheckStateChanged({
         $okButton.Enabled = $True -in $checkboxes.Value.Checked
    })
}

Everything works fine when I have created objects on start. But when I create checkboxes dynamically during program works then I have some errors because method Add_CheckStateChanged refers to a non-existent object (checkboxes). Of course program run fine, and check the state of checkboxes, but it also output errors:

Method invocation failed because [System.Boolean] does not contain a mathod named 'Add_CheckStateChanged'

Do You know some way to around this errors (without Out-null) or some way to check state of checkboxes only after creating them.

I also try "try catch" block. But in this situation Add_CheckStateChanged not work properly.