[SOLVED] How can a lineedit accept only (ASCII alphanumeric character required. A-Z, a-z, 0-9.)

[Leon]

I am seeing "this":http://doc.qt.nokia.com/latest/qlineedit.html#inputMask-prop but i can't understant what to put at the inputmask at qtdesigner..

!http://img689.imageshack.us/img689/5366/screenshot1oa.png(screen)!

This isn't correct. So how to accept only A-Z,a-z and 0-9?

[koahnig]

to solve your problem, you may use the "QRegExpValidator":http://doc.qt.nokia.com/4.7/qregexpvalidator.html
@
lineEdit->setValidator(new QRegExpValidator( QRegExp("\w"), this ));
@

I have used recently the QRegExpValidator instead of inputMask for very same reason. Please verify the validity of the RegExp I defined.

[octal]

\w is equivalent to [A-Za-z0-9_]. For alphanumeric characters, you may want to use [A-Za-z0-9]

[Leon]

Thanks for the answers. But with

@ ui->lineEdit->setValidator(new QRegExpValidator( QRegExp("[A-Za-z0-9_]"), this ));
@

i cant write more than one letter/number at the lineedit when i run the program.

[Leon]

Hmm as seen "here":http://developer.qt.nokia.com/forums/viewthread/8432 with this it works fine.

@ ui->lineEdit->setValidator(new QRegExpValidator( QRegExp("[A-Za-z0-9_]{0,255}"), this ));
@

So adding {0,255} let me put more than i letter. But why? is this correct like this?

[dangelog]

Because that's how regexps work? The class "[A-za-z0-9]" matches one character belonging to that class. To match more you have to use a quantifier (f.i. * for an unbounded number of repetitions).

[octal]

Well, I'm not a regexp specialist but that's how regexp work. [A-Za-z0-9_] only matches one character.

If you want to match an undefined amount of characters, you'll have to use one of these metacharacteres :

• '*' Matches zero or more times ;
• '+' Matches one or more times.

For example :

@ui->lineEdit->setValidator(new QRegExpValidator( QRegExp("[A-Za-z0-9_]+"), this ));@

If I'm not wrong, you can also use :

@[A-Za-z0-9_]{1,}@

[Leon]

Ok thank you guys! :)