Can someone tell me how I could create a Non Modal Dialog in MFC's Visual c++ 6.0 and show it?
I wrote this code:
CDialog dialog;
if (dialog.init(initialization values...))
dialog.DoModal();
But it blocks my application from showing the dialog. I dont know if there exists any method or other way to do it.
Thanks
/* CChildDialog class is inherited from CDialog */
CChildDialog *m_pDialog = NULL;
// Invoking the Dialog
m_pDialog = new CChildDialog();
if (m_pDialog != NULL)
{
BOOL ret = m_pDialog->Create(IDD_CHILDDIALOG, this);
if (!ret) //Create failed.
{
AfxMessageBox(_T("Error creating Dialog"));
}
m_pDialog->ShowWindow(SW_SHOW);
}
// Delete the dialog once done
delete m_pDialog;
Use CDialog::Create and then use CDialog::ShowWindow. You now have a modeless dialog box.
You can call CDialog::Create and CWnd::ShowWindow like the others have suggested.
Also, keep in mind your dialog will be destroyed right after its creation if it is stored in a local variable.
In this case I find it most convenient to let it self-delete itself to handle the cleanup.
Often it's considered bad form to make "implicit" memory freeing from within a class, and not by what it created it, but I usually make exceptions for modeless dialog boxes.
That is;
Calling code:
#include "MyDialog.h"
void CMyApp::OpenDialog()
{
CMyDialog* pDlg = new CMyDialog(this);
if (pDlg->Create(IDD_MYDIALOG, this))
pDlg->ShowWindow(SW_SHOWNORMAL);
else
delete pDlg;
}
Dialog code:
void CMapBasicDlg::OnDestroy()
{
CDialog::OnDestroy();
delete this; // Shown as non-modal, we'll clean up ourselves
}
You need to call CDialog::Create instead. You will need to call DestroyWindow when you are finished with the dialog. You might also need to pass dialog messages onto the object but I can't remember if MFC handles this for you or not.
DoModal is blocking. You have to create your dialog on the heap or make it a member of your class (this is important), call Create then call ShowWindow.
Related
I am running into the following issue:
Users presses "Ctrl+N" which goes into function MainWindow::newAction()
In MainWindow::newAction(), create a QDialog dlg(centralWidget()) and call dlg.exec()
While dlg is open, users pressed "Ctrl+N" again
The result is that dlg never gets deleted (it will only get deleted once centralWidget() gets deleted).
The call stack is something like this:
MainWindow::newAction ()
...
MainWindow::newAction()
I am wondering how to handle this case. I want all of the local dialog variables from the first call to newAction() to be deleted by the time we go into the function newAction() again.
You also can try something like this:
void MainWindow::newAction() {
const auto dialog = new MyDialog(centralWidget());
// When user will close the dialog it will clear itself from memory
connect(dialog, &QDialog::finished, [dialog]() {
dialog->deleteLater();
});
dialog->exec();
}
However, a good move would be to stop user from summoning more QDialogs than a single one, given that this one is a modal dialog(might be a good idea to keep this dialog pointer as a class member and check is it on screen already before calling exec() on it.
If i understood the question right, you want one dialog to be opened and want to delete it before a new dialog request comes in?
If that's the case you can do following:
In MainWindow.h declare QDialog *dlg = nullptr
In your MainWindow.cpp newAction() function you can do following:
void newAction()
{
if(dlg != nullptr)
{
dlg->close();
dlg->deleteLater();
//or
//dlg->destroy(); // this will immediately free memory
}
dlg = new QDialog(centralWidget());
...
//dlg->exec(); // This will automatically make QDialog modal.
dlg->show(); // This will not make a QDialog modal.
}
I hope this will help. Remember QDialogs when displayed with exec() they automatically behave as Modal window. show() will make it non-modal.
I am new to MFC and have built an "outlook" style MFC app using the wizard. I've extended the CMFCShellTreetCtrl using CMyShellTreeCtrl and had data member variables and all was working fine. Now I want to move the data over to the CDocument class. Since there is several accesses to the data as each item is clicked or enumerated, I thought I would create a member variable m_pDoc to access the public variables in the CDocument. The problem I'm having, I can't find where to get the CDocument as it appears it's not setup when the trees OnCreate is called. That is in OnCreate
CWnd* pWndMain = AfxGetMainWnd();
ASSERT(pWndMain);
ASSERT(pWndMain->IsKindOf(RUNTIME_CLASS(CFrameWnd)) && !pWndMain->IsKindOf(RUNTIME_CLASS(CMDIFrameWnd))); // Not an SDI app.
m_pDoc = (CMyDoc*) ((CFrameWnd*)pWndMain)->GetActiveDocument();
returns NULL in m_pDoc and if I tried in an AfterCreate() (which is called after CreateOutlookBar) it's too late as m_pDoc is already being used and get a crash.
// Create and setup "Outlook" navigation bar:
if (!CreateOutlookBar(m_wndNavigationBar, ID_VIEW_NAVIGATION, m_wndTree, m_wndCalendar, 250))
{
TRACE0("Failed to create navigation pane\n");
return -1; // fail to create
}
m_wndTree.AfterCreate();
Any Ideas?
TIA!!
I came up with the following but I'm not sure if this is the proper way. Again, I'm new to MFC (I always have used Win32 directly). This works so it's AN answer, but is it THE correct answer?
POSITION docpos = AfxGetApp()->GetFirstDocTemplatePosition();
CDocTemplate *doctemplate = AfxGetApp()->GetNextDocTemplate(docpos);
docpos=doctemplate->GetFirstDocPosition();
m_pDoc = (CMyDoc*)doctemplate->GetNextDoc(docpos);
ASSERT(m_pDoc);
ASSERT(m_pDoc->IsKindOf(RUNTIME_CLASS(CMyDoc)));
TIA!!
I have an MFC dialog based application that has 2 Dialogs: Main Dialog CMyDlgand Second dialog CMyDlg2.
On the main Dialog I add a Button "Go dialog 2". So I added a handler for the button so that when clicked it pops up the second dialog. Everything works fine But on the second Dialog I have added a Rich Edit Control from toolbox. I Added for it a variable. I also added a class for the second dialog.
Now If I run the Application I get the dialog one and if I pressed "Go to dialog 2" I got what I want. But I need at some point to change the font of the rich edit control but my program crashes.
So I overrided OnInitDialog and inside it do some changes to the control but program crashes. After debugging I found that the handle of rich edit is null?!
So how and where can I change the color or do some initializations to the control?
(I called AfxInitRichEdit2() in OnInitInstance())
BOOL CMyDlg2::OnInitDialog() {
m_richEdit.SetWindowText("Hello there!"); // program crashes because the handle m_richEdit is null.
return TRUE;
}
And this is the handler of button that creates the Dialog2 and that contains the rich edit control:
void CMyDlg::OnBnClickedButton1(){
CMyDlg2 theDlg;
theDlg.DoModal();
// TODO: Add your control notification handler code here
}
If I create the rich edit control programmatically then everything works fine because I create it at OnInitDialog and then it works fine but I need the one that is I added using the wizard toolbox.
*** The thing is that if I write:
m_richEdit.SetWindowText(""); // program crashes but if I wirte:
GetDlgItem(IDC_RICHEDIT221).SetWindowText(""); it works fine?
You probably have the following code inserted by wizard:
void DoDataExchange(CDataExchange* pDX)
{
CDialogEx::DoDataExchange(pDX);
DDX_Control(pDX, IDC_RICHEDIT22, m_richEdit);
}
This tells the dialog to associate m_richEdit with the dialog control IDC_RICHEDIT22. But this association is not performed until the base class method CDialog::OnInitDialog(); is called.
BOOL CMyDlg2::OnInitDialog()
{
//this line should work:
GetDlgItem(IDC_RICHEDIT22)->SetWindowText("Hello");
//this line won't work:
//m_richEdit.SetWindowText("Hello there!"); <- richedit's handle is NULL
//this line will subclass m_richEdit
//plus run other initialization
CDialog::OnInitDialog();
//m_richEdit is ready
m_richEdit.SetWindowText("Hello there!");
return TRUE;
}
It's recommended to put CDialog::OnInitDialog() int the first line, to make sure the initialization is done.
GetDlgItem works because the control IDC_RICHEDIT22 exists in the dialog template and you have a valid dialog handle. You are basically making a simple call based on WinAPI's GetDlgItem:
HWND hedit = ::GetDlgItem(m_hWnd, IDC_RICHEDIT22);
::SetWindowText(hedit, "Hello world");
There is no additional initialization needed.
But m_richEdit is just a C++ object, declared as CRichEditCtrl m_richEdit; The constructor for this C++ class doesn't do much besides setting m_hWnd to NULL.
Once it's associated with a valid window handle, we can begin using its windows methods such as CRichEdit::SetWindowText
For now I can do:
void MainWindow::on_actionPATH_triggered() {
std::unique_ptr<QDialog> win(new QDialog());
win->exec();
}
Should I use async / run in separate threadto avoid blocking main window or is there way to subscribe to close even and delete / free object there?
You can use just show()
void MainWindow::on_actionPATH_triggered() {
QDialog* win = new QDialog();
//needed connect
win->setAttribute(Qt::WA_DeleteOnClose);//we don't want memory leak
win->show();
}
and use
win->setModal(false);//but it is default option, you don't need to change it
From doc:
By default, this property is false and show() pops up the dialog as
modeless. Setting his property to true is equivalent to setting
QWidget::windowModality to Qt::ApplicationModal. exec() ignores the
value of this property and always pops up the dialog as modal.
Qt::WA_DeleteOnClose will delete your dialog, when user close it.
You can also set parent to dialog:
QDialog* win = new QDialog(this);
In this case win will be delete with your mainWindow.
Info about Qt parent child relationship
And you don't need here separate thread.
class MyApp : public CWinApp {
afx_msg OnPrefrences();
};
OnPrefrences() get called when user selects tools->Preference from the menubar.
Now in one dialog(Say DlgX) there is one button, on clicking this I need to open the Preference dialog which has in fact many panes, but here I need to open the Preference dialog by selecting one the these pane as active. Also in that particular pane I need to hide some of the controls only when It gets open through this the dialog not through menu.
So I have created one variable(Say m_varX) in MainFrm class.
void DlgX::OnButtonXClick()
{
CMainFrame* pFrame = (CMainFrame*)AfxGetMainWnd();
if(pFrame)
{
pFrame->m_varX = TRUE;
((CMyApp*)(AfxGetApp()))->OnPrefrences();
pFrame->m_varX = FALSE;
}
}
And in button handler of DlgX I have made this m_varX TRUE and call the OnPreference() and after closing of this preference dialog I have made m_varX FALSE.
All this is working fine... But the problem is that things gets clutter in mainFrm. Also the project I am working on is legacy one so I cant make much changes.
Is there any patter available for handling such case?
Thanks
You could solve this with a custom dialog (if you don't have it already)
When you show the dialog from the main menu i.e. onPreferences() you fill and show all 'panes'. you would have to do a custom dialog where the ctor takes some arguments.
E.g.
enum { all, part };
void MainFrame::OnPreferences()
{
CMyPreferences dlg( GetDocument(), all );
dlg.DoModal();
}
but when you call it from within a dialog you only fill in the parts you need.
void YourDialog::OnPreferences()
{
CMyPreferences dlg( GetDocument(), part );
dlg.doModal();
}
The argument could be something more sophisticated for more fine tuned configuration of what to show/allow to edit.
I think for that special case, even if sometimes is no more considered a pattern, the singleton pattern would work for you.