Well i started working on this a while back and quit on it about a few weeks ago so i decided i would just release it with the source.
What it does right now is it can load a file and show the text and hex. It can also add bytes to the file and it has a hex calculator that does nothing, cool right?

It is VERY SLOW. It's because i never loaded the text a proper way and i used a for statement. Aslo i never got around to fixing the save function so it doesn't save.
Not Recommended loading anything over 3kb.
And if someone uses this code for some odd reason then give me credit at least.
Well here it is
