I got 3 questions.

1. With my program, I get the filename from the file and store it in a string after they open it and after they use Save As. My question is, how can I get JUST the filename like when I get the entire file it will show the directories under it, I just want like "file.txt" and not "C:\file.txt". Also, how could I just get what extension is on it?

2. I created a new form for a preferences dialog. I was wondering, how could I use a treeview to display things on the dialog? I don't want to put 10 things on each group and have like 10 groups then hide them all and show 1 when clicking on a tree, because then it would be A MESS to edit and change things.

3. I want to draw a line on a textbox. How can I do that? I want it to be exactly on a margin that doesn't exist. Like say I want a red line to be drawn on margin 800 even though the text box will go past that. how

Okay, after this I doubt I'll have any questions for a good while. I posted to see what you guys recommend and see what the best/better ways are, however, I am also searching/looking for solutions too