Qt C++: Line edit accept only alphanumeric characters, dash and underscore

Question

I'm looking for the way to limit line edit to accept only alphanumeric characters, dash and underscore (in whole line could be only one dash and one underscore), without spaces. I was looking at RegExp, but then I left this option, because I found some blog post which is explaining that RegExp is really slow. Now I don't know what is best way to limit line edit, so the output would be like I want.

What do you recommend me?

Answer 1

You should read function QLineEdit::setValidator documentation and class QValidator documentation. You can define your own validator class (that inherits QValidator) and pass its object instance to QLineEdit object (using setValidator function).