How to convert QString to QDate in specific format?

Question

I have a QDateEdit in my GUI from which I convert the QDate to QString and add it to my database. The QString date is saved in the database in this format: 20/12/2015.

In case a user want to edit the date, then I need to show the date on the QDateEdit field on the GUI again. Hence, I need to fetch the database, bring back the date (which is in QString format) and convert it to QDate back again in order to put it on the QDateEdit field on the GUI.

However, I cannot manage to convert that QString format (i.e.: 20/12/2015) to QDate using the following:

QString date_string_on_db = "20/12/2015";
QDate Date;
Date.fromString(date_string_on_db,"dd/MM/YYYY");

The Date is always returning invalid.

what should I do ?

Try using `dd/MM/yyyy` for the format string. – Daniel Kamil Kozar Dec 20 '15 at 15:11 — Daniel Kamil Kozar, Dec 20 '15 at 15:11

score 27 · Accepted Answer · answered Dec 20 '15 at 15:19

First of all, the format string should be dd/MM/yyyy. Qt documentation for the QDate class says that yyyy is recognized as a four digit year number.

Second of all, fromString is a static function that returns a new QDate. Currently, the return value of that function is discarded : it is not written back into the Date variable, as you might think. The complete correct code should therefore look like this :

QString date_string_on_db = "20/12/2015";
QDate Date = QDate::fromString(date_string_on_db,"dd/MM/yyyy");

This worked, but note to the Americans like me that tried copy and paste and it didn't work: it should be "MM/dd/yyyy" for US dates — Matt Binford, Jun 15 '21 at 17:53

How to convert QString to QDate in specific format?

1 Answers1