I'm trying to determine how many characters will fit in a textbox.

Example: A text box will contain a directory path. I would like to be able to calculate, based on how wide the box is and what font is in use, how many characters that box will display. That way I can display the first 10 characters of the path, some periods and the last however many characters that will fit in the box. ex: D:\The Path\....\Some More Path.

Hope that meakes sense.