How to validate string in line edit
I want to check if the input string in line edit starts with only alphabet or number.
sierdzio Moderators last edited by
Many ways to do this. You can react to QLineEdit::textChanged() or use "QLineEdit::setValidator()":http://qt-project.org/doc/qt-4.8/qlineedit.html#setValidator for example.
If you do not want to block the input so that he cannot write anything other than alphabet or number, you could check this with QLineEdit::editingFinished() and if the string is not valid display a message
I have used setValidator in textChanged() of LineEdit but it is not working consistently.
First time it works then if i switch to other window and come back then that line edit will allow all characters.
What is going wrong?