VS 2010 Giving a certain number based on a certain character in a textbox.

Hi, this is my first post. And I am pretty much brand new to Visual Basic so go easy :)
I am creating a simple project for my electronics course in school that converts a character into binary that can be used on a micro-controller in a 7 segment display.
Basically, I am trying to put a letter in and get a number out.

This is converting a number to binary like so (this works):
This is converting a character to binary like so (this doesn't work):
This is probably stupidly basic, but I have searched around and I have found little on this. I want it not to convert it to the number, but to check if it is the certain character and display a certain number.

Thanks in advance :)