Value from Textbox Into Array

Hi...

I have been using a PS script to add printers remotely to PC's in my org; and its been great.  I now want to convert this into a windows form for various reasons.

So I have the form created and now I want to pull the value(s) from it and put them into an array (and here's where I am stuck)...

In my script I have the following to get started.  How would I pull the values from the field txtComputers?

$HostName = @("H24353","H22788")

Foreach($PC in $HostName)