QFileDialog::getOpenFileName() hangs in Windows when using the native dialog

kasunf · wrote on 14 Dec 2014, 22:03

Hi,

I'm using QT 5.3.1 and I noticed that my program hangs in Windows 7 (64bit) with following arguments to the function.

QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"),
"/home",
tr("Images (*.png *.xpm *.jpg)"));

However, if I use the option QFileDialog::DontUseNativeDialog, then it won't hang and will show the non-native file open dialog. I would prefer to use the native windows dialog so can anyone tell me if this is a bug or not?

SGaist · wrote on 14 Dec 2014, 22:44

Hi and welcome to devnet,

Strange but are you aware that you are trying to open a probably non existent folder ? There's no /home on windows. However you can use QDir::home() to get the current user home path

kasunf · wrote on 14 Dec 2014, 22:57

Yes, this is just an example syntax for this post.
My syntax is as follows:

fileName = QFileDialog::getOpenFileName(this,
tr("Select file"),
QString(),
tr("Files (*.cvs *.svf *.txt)"));

SGaist · 5 Nov 2015, 10:33

Do you have any network drive ?

kasunf · wrote on 14 Dec 2014, 23:17

No I don't. I just have a C:\ drive and couple of removable drives, which are not active.
This problem was reproduced on another PC other than mine.

[quote author="SGaist" date="1418598787"]Do you have any network drive ?[/quote]

SGaist · 17 May 2015, 22:19

Which version of Windows ?

kasunf · wrote on 15 Dec 2014, 21:45

It is Windows 7 Professional (64bit).

Looking at the history of Qt, I think this possibly has been a bug for some time (possibly since QT4)....
I have seen at least 1 reported case of this sort of behaviour....

[quote author="SGaist" date="1418678949"]Which version of Windows ?[/quote]

htettey · S SGaist 15 Dec 2014, 21:29

@SGaist

I have just recently migrated a project I am working on to Qt5.4.1 from Qt4.8.5, and I am having the same problem as reported by kasunf.

A call to getOpenFileName hangs - using QFileDialog::DontUseNativeDialog gets it working, but I'll prefer to use te native windows dialog. The code snippet is shown below:

m_imageFile = QFileDialog::getOpenFileName(this, tr("Open Image"), QDir::homePath(), tr("Image Files (*.png *.jpg *.bmp)"), 0, QFileDialog::DontUseNativeDialog); //works

m_imageFile = QFileDialog::getOpenFileName(this, tr("Open Image"), QDir::homePath(), tr("Image Files (*.png *.jpg *.bmp)")); //does not work

Program control does not seem to return from this function call. Has this issue been resolved? My system specifications are as follows:

Windows7 64bit
Visual Studio 2010
Qt5.4.1_opengl

PS: I did not have this problem with Qt4.8.5

Thanks,

SGaist · 20 May 2015, 06:38

Do you mean that when you click OK the dialog disappear but your application doesn't do anything ?

htettey · S SGaist 19 May 2015, 21:44

@SGaist Nope, that is not what I mean.

The open fIle dialog does not appear at all - as though my application is waiting for it to appear. After investigations it turns out that it seems to hang in the call to

QFileDialog::getOpenFileName(...)

As I indicated, a call to QFileDialog::getOpenFileName(...) using the flag QFileDialog::DontUseNativeDialog returns from the function call, but the same function call without using the flag does not return.

I will like to use it without the flag. Also, I didn't have this problem in Qt4.8.5.

Please this is the same problem as first reported on this post. I just need to know what the status of this issue is.

PS: I am interested in purchasing a commercial license for Qt5, but I need to make sure that my project works in Qt5 before going ahead with the purchase.

Thanks,

SGaist · wrote on 28 May 2015, 21:20

Which compiler are you using ? Just tested with VS2013 on Win 8 and no problem with the dialog.

GirishJ · wrote on 18 Aug 2015, 11:02

Facing exactly same problem on Windows 7 pro (64-bit) with Qt5.5 MSVS2010 Professional with Qt Add-in.

mrjj · wrote on 18 Aug 2015, 12:02

win 7. 64 bit, Qt 5.5, "gcc"
No hanging at all.
So maybe only VS?

Please Try with QFileDialog::DontUseCustomDirectoryIcons
As i had case where it would take ages due to subversion overlay icons.

Rondog · wrote on 18 Aug 2015, 12:43

I have used most of the Qt versions mentioned in this thread and never had a problem with using the getOpenFileName(...) member function with native dialogs. I have always used MinGW for Windows so maybe this problem is unique to Visual Studio?

Wesley · wrote on 5 Nov 2015, 10:33

@SGaist said:

Do you have any network drive ?

I have a problem using the functions QFileDialog::getSaveFileName and QFileDialog::getOpenFileName on a PC with many network drives. Could you please help on this? Thanks.

dan-42 · wrote on 26 Apr 2019, 09:03

Just to note this issue still exists, but does not happen on all QFileDialogs instances used in our software.

When does it work:

On the very first start-screen, when no other backend-threads are running, no COM connection is created etc.

When does it not work

Some where later in the application, when backend-threads are running, COM connection to a different application is established.

Setup:

Qt 5.12.3
MSVC 2017 v15.9.7
Windows 10 build1809

The issue is reproducible on different computers in Debug and Release Build

Observations

Opening The QFileDialog leads to the following:

The Main-UI is blocked and you can hear the windows-sound that comes, when the UI is blocked because a Dialog is in front and the user clicks somewhere on the Main-UI.

Then

Switching between applications (Alt-Tab) then hitting ESC, and the Main-UI is responsible again.
This indicates, that there is an invisible Dialog on top of the main-UI.

Opening The QFileDialog again

Then it works!

Gwen5484 · wrote on 29 Aug 2019, 16:05

Same symptoms here, with QFileDialog::getExistingDirectory.

Before loading the COM objets, the dialog opens well, with native window.
After laoding COM (CoInitializeEx), calling getExistingDirectory causes the program to hang.
After disconnecting COM (CoUninitialize), the dialog opens well again, but with Qt window (not native) even though I did'nt specify the DontUseNativeDialog option!

Qt 5.12.1, MSVC 2017, Windows 10

JonB · wrote on 29 Aug 2019, 16:57

Clearly nasty COM behaviour. I am not a Qt expert, but since your post and the previous one are nice and clear on the reproducibility, the best would be to (search first and then) report them at https://bugreports.qt.io/secure/Dashboard.jspa, see also https://wiki.qt.io/Reporting_Bugs.

Vortex0911 · wrote on 7 Jun 2024, 17:49

Yeah I am encountering the same problem in 2024. This condition is also caused by QSplitter for some reason. Setting my "central" widget to QSplitter just causes it to permanently block a thread for some reason. But somehow setting the don't use native dialog option allows me to open it. If you have some suggestion for me do tell as I am a complete noob

Richard · wrote on 18 Jun 2024, 08:15

We encountered this problem years ago. And this was caused by programs from DELL, "Dell Backup and Recovery", "Dell Optimizer", "Dell Power Management". These programs use Qt too, even statically compiled, but in a nasty way that prevented using newer Qt versions. And it crashed our software when you open a file dialog using native dialog on windows. Problems were solved once these programs were uninstalled.