How to retrieve a device name from IP or MAC on LAN

In Visual Studio 2015, VB, in Windows 10, I have a small program where I use the arp -a command
to pick up the mac and I/P addresses of connected devices on my lan. From everything I've read (and tried), the answer
somehow comes back to DNS.getHostEntry which throws a No Such Host when fed a cell's I/P and
I understand that, a cell phone is not a host. Does anyone know of the appropriate DNS or other type
command that, fed an I/P or MAC will return the device's name?

Thank you.

Underscore removed from Checked Listbox

In Visual Studio 2015, under Windows 7, I've created a VB application that fills a Checked Listbox with file names from one of my folders.
Some of the file names contain an underscore character but when shown in the listbox, that character
is replaced with a space. In the code, when I select that item and move its contents to a labelbox, the underscore shows up.
Is there a simple Tool > Option I'm missing in set up? (I've read about textblock and not at all happy with that solution.)

Thank you,
Paul