Finding out the Line number of a Textbox

Okay, I want to save each line of a textbox as a string. For example, pretend that the text below is in a textbox.

*******************************************
Hello
This
is
a
textbox!
*******************************************

When I press the button, I want to save each line as a seperate string, so when I save it, the file would look like this:

"Hello","this","is","a","texbox1"