PowerShell Windows Forms Tutorial 3 : SHA1 Hash Checker

Another video to add to my series of PowerShell Windows Forms tutorial. In this one, we are once again going back to Tutorial 1, where we created a simple dialog box (see start code below). We will then modify the original code, to now include text boxes, buttons and labels. Finally, we will build a function that relies on Windows' pre-built classes to generate the SHA1 hash from an input file. Useful for Android ROM flashers, Windows ISO downloaders...or any other files where the file host provides the hash to compare against!

Start code:
https://pastebin.com/v3KMc2ni

Final code:
https://pastebin.com/wfMEjAWY