How can I get a TextLineEdit object, and capture a key event?

[Kermit Mei <kermit mei gmail com>]

Hello, I'm a newbie for gtkmm, in my program, I need a TextEdit which
can just handle only one line text?

And I must capture the keyboard's event in it.

For example, when I press the key "5", it should show the text "%" but 
not "5".

Thanks.
Kermit Mei