Disable Close button (X) of a QDialog

[BrainB0ne]

Do you get any errors or it just doesn't work?

See http://doc.trolltech.com/3.3/qt.html#WidgetFlags-enum.
Play with different combinations until you get some result. But it really depends on the window manager to respect the flags.

With the Winapi code I first get the following errors:

#ifdef Q_WS_WIN
 
   CMenu* menu = m_pParent->GetSystemMenu(FALSE);
   menu->ModifyMenu(SC_CLOSE, MF_BYCOMMAND | MF_GRAYED );
 
#endif

#ifdef Q_WS_WIN

   CMenu* menu = m_pParent->GetSystemMenu(FALSE);
   menu->ModifyMenu(SC_CLOSE, MF_BYCOMMAND | MF_GRAYED );

#endif

To copy to clipboard, switch view to plain text mode 

: error C2065: 'CMenu' : undeclared identifier
: error C2065: 'menu' : undeclared identifier
: error C2039: 'GetSystemMenu' : is not a member of 'QWidget'
: see declaration of 'QWidget'
: error C2227: left of '->ModifyMenu' must point to class/struct/union
: error C2065: 'SC_CLOSE' : undeclared identifier
: error C2065: 'MF_BYCOMMAND' : undeclared identifier
: error C2065: 'MF_GRAYED' : undeclared identifier


After that i include the <afxwin.h> include file (for CMenu class)
Then the following errors show up:
C:\Program Files\Microsoft Visual Studio\VC98\MFC\INCLUDE\afx.h(226) : warning C4005: 'ASSERT' : macro redefinition
C:\Qt\3.3.4\include\qglobal.h(1010) : see previous definition of 'ASSERT'
: error C2039: 'GetSystemMenu' : is not a member of 'QWidget'
C:\Qt\3.3.4\include\qwidget.h(60) : see declaration of 'QWidget'

[jpn]

That's MFC, not WinAPI...

#include <QtGui>
#ifdef Q_WS_WIN
#include <qt_windows.h>
#endif // Q_WS_WIN
 
int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
	QWidget window;
 
#ifdef Q_WS_WIN
	HMENU menu = ::GetSystemMenu(window.winId(), FALSE);
	::DeleteMenu(menu, SC_CLOSE, MF_BYCOMMAND);
	::EnableMenuItem(menu, SC_CLOSE, MF_BYCOMMAND | MF_GRAYED);
	// or (removes the item in of system menu)
	// ::DeleteMenu(menu, SC_CLOSE, MF_BYCOMMAND);
#endif // Q_WS_WIN
 
	window.show();
	return app.exec();
}

#include <QtGui>
#ifdef Q_WS_WIN
#include <qt_windows.h>
#endif // Q_WS_WIN

int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
	QWidget window;

#ifdef Q_WS_WIN
	HMENU menu = ::GetSystemMenu(window.winId(), FALSE);
	::DeleteMenu(menu, SC_CLOSE, MF_BYCOMMAND);
	::EnableMenuItem(menu, SC_CLOSE, MF_BYCOMMAND | MF_GRAYED);
	// or (removes the item in of system menu)
	// ::DeleteMenu(menu, SC_CLOSE, MF_BYCOMMAND);
#endif // Q_WS_WIN

	window.show();
	return app.exec();
}

To copy to clipboard, switch view to plain text mode 

[BrainB0ne]

That's MFC, not WinAPI...

#include <QtGui>
#ifdef Q_WS_WIN
#include <qt_windows.h>
#endif // Q_WS_WIN
 
int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
	QWidget window;
 
#ifdef Q_WS_WIN
	HMENU menu = ::GetSystemMenu(window.winId(), FALSE);
	::DeleteMenu(menu, SC_CLOSE, MF_BYCOMMAND);
	::EnableMenuItem(menu, SC_CLOSE, MF_BYCOMMAND | MF_GRAYED);
	// or (removes the item in of system menu)
	// ::DeleteMenu(menu, SC_CLOSE, MF_BYCOMMAND);
#endif // Q_WS_WIN
 
	window.show();
	return app.exec();
}

#include <QtGui>
#ifdef Q_WS_WIN
#include <qt_windows.h>
#endif // Q_WS_WIN

int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
	QWidget window;

#ifdef Q_WS_WIN
	HMENU menu = ::GetSystemMenu(window.winId(), FALSE);
	::DeleteMenu(menu, SC_CLOSE, MF_BYCOMMAND);
	::EnableMenuItem(menu, SC_CLOSE, MF_BYCOMMAND | MF_GRAYED);
	// or (removes the item in of system menu)
	// ::DeleteMenu(menu, SC_CLOSE, MF_BYCOMMAND);
#endif // Q_WS_WIN

	window.show();
	return app.exec();
}

To copy to clipboard, switch view to plain text mode 

Woooow! That did the job! I'm really happy with this solution

[blue.death]

Hi guys,
I'm quite late on this thread but I had the same problem :-)

Anybody knows how to disable that nasty little button on X11 and Mac OS X??

In case you need it, here is a nice macro I am using on Win32 - it's pretty similar to the latest post of course and it works fine:

# ifdef Q_OS_WIN
#  include <windows.h>
#  define ENABLE_CLOSE_BTN(Enable) \
	{ QWidget* tlw = this; \
	while (tlw && !tlw->isWindow() && tlw->windowType() != Qt::SubWindow) \
		tlw = tlw->parentWidget(); \
	HMENU hMenu = GetSystemMenu((HWND) tlw->winId(), FALSE); \
	EnableMenuItem(hMenu, SC_CLOSE, Enable ? (MF_BYCOMMAND | MF_ENABLED) : (MF_BYCOMMAND | MF_GRAYED)); }
# endif // Q_OS_WIN

# ifdef Q_OS_WIN
#  include <windows.h>
#  define ENABLE_CLOSE_BTN(Enable) \
	{ QWidget* tlw = this; \
	while (tlw && !tlw->isWindow() && tlw->windowType() != Qt::SubWindow) \
		tlw = tlw->parentWidget(); \
	HMENU hMenu = GetSystemMenu((HWND) tlw->winId(), FALSE); \
	EnableMenuItem(hMenu, SC_CLOSE, Enable ? (MF_BYCOMMAND | MF_ENABLED) : (MF_BYCOMMAND | MF_GRAYED)); }
# endif // Q_OS_WIN

To copy to clipboard, switch view to plain text mode 

Now just use ENABLE_CLOSE_BTN(true) or ENABLE_CLOSE_BTN(false).

It will detect the top level widget of the widget containing the code, so you can use it inside of a child widget (eg. a wizard page in my case) without having to change the macro
Feel free to replace that "while" loop if you are always going to use it inside of a top level window.

And now on with your suggestions for X11/MAC

[MarkoSan]

How do I hide close, resize and minimize featuers in QGLWidget??

setWindowFlags(Qt::FramelessWindowHint);

setWindowFlags(Qt::FramelessWindowHint);

To copy to clipboard, switch view to plain text mode 

does not work!!

[jpn]

How do I hide close, resize and minimize featuers in QGLWidget??

setWindowFlags(Qt::FramelessWindowHint);

setWindowFlags(Qt::FramelessWindowHint);

To copy to clipboard, switch view to plain text mode 

does not work!!

What do you mean? Are you showing QGLWidget as a top level window? QGLWidget is a QWidget so when it comes to adjusting window flags, anything that works for a plain QWidget should work with QGLWidget as well.

[GokuH12]

Hi guys,
I'm quite late on this thread but I had the same problem :-)

Anybody knows how to disable that nasty little button on X11 and Mac OS X??

In case you need it, here is a nice macro I am using on Win32 - it's pretty similar to the latest post of course and it works fine:

# ifdef Q_OS_WIN
#  include <windows.h>
#  define ENABLE_CLOSE_BTN(Enable) \
	{ QWidget* tlw = this; \
	while (tlw && !tlw->isWindow() && tlw->windowType() != Qt::SubWindow) \
		tlw = tlw->parentWidget(); \
	HMENU hMenu = GetSystemMenu((HWND) tlw->winId(), FALSE); \
	EnableMenuItem(hMenu, SC_CLOSE, Enable ? (MF_BYCOMMAND | MF_ENABLED) : (MF_BYCOMMAND | MF_GRAYED)); }
# endif // Q_OS_WIN

# ifdef Q_OS_WIN
#  include <windows.h>
#  define ENABLE_CLOSE_BTN(Enable) \
	{ QWidget* tlw = this; \
	while (tlw && !tlw->isWindow() && tlw->windowType() != Qt::SubWindow) \
		tlw = tlw->parentWidget(); \
	HMENU hMenu = GetSystemMenu((HWND) tlw->winId(), FALSE); \
	EnableMenuItem(hMenu, SC_CLOSE, Enable ? (MF_BYCOMMAND | MF_ENABLED) : (MF_BYCOMMAND | MF_GRAYED)); }
# endif // Q_OS_WIN

To copy to clipboard, switch view to plain text mode 

Now just use ENABLE_CLOSE_BTN(true) or ENABLE_CLOSE_BTN(false).

It will detect the top level widget of the widget containing the code, so you can use it inside of a child widget (eg. a wizard page in my case) without having to change the macro
Feel free to replace that "while" loop if you are always going to use it inside of a top level window.

And now on with your suggestions for X11/MAC

Woo so good! thx for the nice macro! its works just nice

[shad]

Starting with Qt 4.5 there is a new window hint for controlling close button Qt::WindowCloseButtonHint:

QWidget w;
w.setWindowFlags(Qt::Window | Qt::CustomizeWindowHint | Qt::WindowTitleHint| Qt::WindowSystemMenuHint | Qt::WindowMinMaxButtonHint);

QWidget w;
w.setWindowFlags(Qt::Window | Qt::CustomizeWindowHint | Qt::WindowTitleHint| Qt::WindowSystemMenuHint | Qt::WindowMinMaxButtonHint);

To copy to clipboard, switch view to plain text mode 

[BrainB0ne]

Starting with Qt 4.5 there is a new window hint for controlling close button Qt::WindowCloseButtonHint:

QWidget w;
w.setWindowFlags(Qt::Window | Qt::CustomizeWindowHint | Qt::WindowTitleHint| Qt::WindowSystemMenuHint | Qt::WindowMinMaxButtonHint);

QWidget w;
w.setWindowFlags(Qt::Window | Qt::CustomizeWindowHint | Qt::WindowTitleHint| Qt::WindowSystemMenuHint | Qt::WindowMinMaxButtonHint);

To copy to clipboard, switch view to plain text mode 

That's very nice to hear/know when i'm going to use Qt 4.5 or higher in the future!

[MarkoSan]

That's very nice to hear/know when i'm going to use Qt 4.5 or higher in the future!

Very nice, thanks, but, is it possible to disable (X) in dialog that resided on QGraphicsView, I've read in the docs that is NOT possible ...

[sophister]

I use the same code in QT4.5, but it doesn't work!!
why??

[kyue]

Anybody knows how to disable that nasty little button on X11 and Mac OS X??

I have the exact same problem. I'm using Qt 4.3 and don't have the luxury of Qt::WindowMinMaxButtonHint.

I need to keep the title bar empty, so Qt::FramelessWindowHint makes the message box a bit bare.

It was suggested that we can inherit a QDialog box and disable it there...would anyone else know of any other suggestions?

Thanks,
Kat

[shad]

It was suggested that we can inherit a QDialog box and disable it there...would anyone else know of any other suggestions?

try upgrading to qt 4.5

[lni]

Try this

#include <qapplication.h>
#include <qevent.h>
#include <qpushbutton.h>
#include <qdialog.h>
#include <qmessagebox.h>
#include <iostream>
 
class MyDialog : public QDialog
{
public:
 
  MyDialog( QWidget* parent=0 ) : QDialog( parent ) {
  }
 
protected:
 
  void closeEvent ( QCloseEvent * event ) {
    event->ignore();
    QMessageBox::information( this, "Close?", "Close? No way!" );
  }
};
 
int main( int argc, char** argv )
{
  QApplication app( argc, argv );
 
  MyDialog dlg;
  QPushButton* button = new QPushButton( "Exit", &dlg );
  QObject::connect( button, SIGNAL( clicked() ),
                    &app, SLOT( quit() ) );
  dlg.resize( 300, 300 );
  dlg.show();
 
  return app.exec();
 
}

#include <qapplication.h>
#include <qevent.h>
#include <qpushbutton.h>
#include <qdialog.h>
#include <qmessagebox.h>
#include <iostream>

class MyDialog : public QDialog
{
public:

  MyDialog( QWidget* parent=0 ) : QDialog( parent ) {
  }

protected:

  void closeEvent ( QCloseEvent * event ) {
    event->ignore();
    QMessageBox::information( this, "Close?", "Close? No way!" );
  }
};

int main( int argc, char** argv )
{
  QApplication app( argc, argv );

  MyDialog dlg;
  QPushButton* button = new QPushButton( "Exit", &dlg );
  QObject::connect( button, SIGNAL( clicked() ),
                    &app, SLOT( quit() ) );
  dlg.resize( 300, 300 );
  dlg.show();

  return app.exec();

}

To copy to clipboard, switch view to plain text mode 

[kyue]

Try this

#include <qapplication.h>
#include <qevent.h>
#include <qpushbutton.h>
#include <qdialog.h>
#include <qmessagebox.h>
#include <iostream>
 
class MyDialog : public QDialog
{
public:
 
  MyDialog( QWidget* parent=0 ) : QDialog( parent ) {
  }
 
protected:
 
  void closeEvent ( QCloseEvent * event ) {
    event->ignore();
    QMessageBox::information( this, "Close?", "Close? No way!" );
  }
};
 
int main( int argc, char** argv )
{
  QApplication app( argc, argv );
 
  MyDialog dlg;
  QPushButton* button = new QPushButton( "Exit", &dlg );
  QObject::connect( button, SIGNAL( clicked() ),
                    &app, SLOT( quit() ) );
  dlg.resize( 300, 300 );
  dlg.show();
 
  return app.exec();
 
}

#include <qapplication.h>
#include <qevent.h>
#include <qpushbutton.h>
#include <qdialog.h>
#include <qmessagebox.h>
#include <iostream>

class MyDialog : public QDialog
{
public:

  MyDialog( QWidget* parent=0 ) : QDialog( parent ) {
  }

protected:

  void closeEvent ( QCloseEvent * event ) {
    event->ignore();
    QMessageBox::information( this, "Close?", "Close? No way!" );
  }
};

int main( int argc, char** argv )
{
  QApplication app( argc, argv );

  MyDialog dlg;
  QPushButton* button = new QPushButton( "Exit", &dlg );
  QObject::connect( button, SIGNAL( clicked() ),
                    &app, SLOT( quit() ) );
  dlg.resize( 300, 300 );
  dlg.show();

  return app.exec();

}

To copy to clipboard, switch view to plain text mode 

Thank you for your reply. Yes, this was a solution that was considered. I'm wondering if there is another solution where we don't have to inherit and ignore the closeEvent...

[kyue]

If this helps anyone, you can remove the three buttons on the top left (close, minimize, maximize) on a Mac and leaving the title there using:

setWindowModality(Qt::WindowModal);

setWindowModality(Qt::WindowModal);

To copy to clipboard, switch view to plain text mode 

[rajesh]

try Window flags
see the example: http://doc.trolltech.com/4.3/widgets-windowflags.html

[totem]

hi

this did the job for me (on a QDialog based class) :

Qt::WindowFlags flags = windowFlags() ;
flags |= Qt::CustomizeWindowHint ;
flags &= ~Qt::WindowCloseButtonHint ;
setWindowFlags( flags ) ;

Qt::WindowFlags flags = windowFlags() ;
flags |= Qt::CustomizeWindowHint ;
flags &= ~Qt::WindowCloseButtonHint ;
setWindowFlags( flags ) ;

To copy to clipboard, switch view to plain text mode 

[kyue]

try upgrading to qt 4.5

Sorry, I didn't see these replies until now. It's not an option for us right now.