Visual Studio 2005, C++, Windows XP.
I have a CDialog with a single button, which calls a function like so:
BEGIN_MESSAGE_MAP(Foo, BaseDlg) //BaseDlg inherits from CDialog
ON_BN_CLICKED(IDBAR, Bar)
END_MESSAGE_MAP()
The dialog box closes when its 'X' is clicked.
I change the above code to:
BEGIN_MESSAGE_MAP(Foo, BaseDlg) //BaseDlg inherits from CDialog
ON_BN_CLICKED(IDBAR, Bar)
ON_BN_CLICKED(IDBAZ, Baz)
END_MESSAGE_MAP()
My dialog window will no longer close. Whenever the X is clicked, Baz() is called. The second ON_BN_CLICKED() handler is replacing the normal dialog close behavior for some reason.
How do I close a dialog box which has two or more buttons mapped to functions?
What are the numeric values assigned to IDBAR and IDBAZ in the resource file? One possible explanation is that IDBAZ == IDCANCEL, which is defined in MFC by default as the ID for both the dialog's cancel and X buttons. Defining your own handler for this constant will then override the default behaviour, which is to close the window. This only applies though if you're showing the dialog modally - if it's modeless then you always have to close the dialog yourself by calling EndDialog().
Related
I want to add a CDialog control inside CDockablePane. When I use CDialog.DoModal() to display the dialog window, it makes the MFC application unresponsive and waiting for the CDialog result.
How can I make the application display the dialog and continue running without waiting for the CDialog result?
You cannot use DoModal to display the dialog. That displays a modal dialog, which prevents interaction with any other windows in your application until the dialog has been dismissed. Just like a message box does.
To display a non-modal dialog, you call the Create member function. Use the instance of your CDockablePane as the dialog's parent. You will also need to ensure that the dialog itself is a child window, without a border.
It might be easier to use a class derived from CFormView or CPaneDialog.
I have a CFormView SDI which calls and opens up a CDialog.
In the CDialog I have a button which has a bitmap displayed.
All works well, until I close the CDialog.
When I open up the same CDialog (using create function), the button appears, and the button's functionality is there, however the bitmap disappears.
Can someone please tell me why the bitmap on the button disappears on subsequent calls to CDialog?
Thank you in advance.
Here is the code:
In the CFormView I have a button that creates the CDialog:
void CTest4View::OnButton1()
{
m_dialog_calculator.Create(IDD_DIALOG1, GetDesktopWindow());
m_dialog_calculator.ShowWindow(SW_SHOW);
}
In the CDialog I have the bitmap put on the button in the InitDialog:
BOOL CCalculator::OnInitDialog()
{
CDialog::OnInitDialog();
if(!bitmapNew.LoadBitmap(IDB_BITMAP_NEW)){
MessageBox("problem in loadbitmap");
}
if(!m_button.SetBitmap(bitmapNew)){
MessageBox("problem in SetBitmap");
}
bitmapOpen.LoadBitmap(IDB_BITMAP_OPEN);
m_buttonOpen.SetBitmap(bitmapOpen);
//==========================
return TRUE; // return TRUE unless you set the focus to a control
// EXCEPTION: OCX Property Pages should return FALSE
}
Upon further investigation, the problem seems to be in: m_button.SetBitmap(bitmapNew) since this returns FALSE. Can someone please help me?
Quick fix:
void CTest4View::OnButton1()
{
// only create the dialog once
if (m_dialog_calculator.m_hWnd==NULL)
m_dialog_calculator.Create(IDD_DIALOG1, GetDesktopWindow());
m_dialog_calculator.ShowWindow(SW_SHOW);
}
Additional information 1:
The information that OP provided in his question/code is quite little, so I actually have to recreate a similar test project to guess what is wrong with the missing bitmap. What I found is that the CDialog and CBitmap is being created multiple times when the button is pressed, this causes subsequent creation api call to fail, other than the first creation call. The result is some unexpected behavior as you can see now.
The program is supposed to generate some assertion errors when run in debug mode due to the creation failure but I guess the OP compiled it in release mode so all warnings are being suppressed.
The problem occurred because the calculator dialog is created as a modeless dialog as compared to a normal DoModal way of activation. The usual way of doing such modeless dialog is to create the dialog only once, by monitoring the m_hWnd member variable. When the user want the dialog to be dismissed, it is simply being hidden instead of being destroyed. This will avoid all the multiple creation problems altogether.
I guess presently, the calculator dialog is assumed to be closed and destroy by clicking the "X" button on the top right of dialog, well, actually it is only hidden but not actually being destroyed by the default handling of CDialog. The correct way to dismiss the modeless calculator dialog is thus to overide the OnClose event to hide it using ShowWindow(SW_HIDE). To activate it again, use ShowWindow(SW_SHOWNORMAL).
I have a dialog IDD_WINDOW_INFO that has to be opened when the user clicks a button or a menu item in my C++ Win32 application. The method that I use to open the dialog is in the following line:
DialogBox(hInstance, MAKEINTRESOURCE(IDD_WINDOW_INFO), hMainWindow, WindowInfoProc);
but my problem is that when that dialog box opens, the user cannot operate with the main window of my application. So what can I do to have both windows active?
You are calling DialogBox which shows the dialog modally. When a modal dialog is shown, the other owning windows are disabled and only the modal dialog can accept input. That is the very essence and intent of a modal dialog. The idea is that you can interact only with the dialog, and cannot interact with the other windows.
Another answer suggests passing NULL as the hWndParent parameter to DialogBox. That's not the solution. That will result in you having an unowned window. Yes, you will be able to interact with the main window, but when you do so your main window will appear on top of the dialog. That's because the ownership is set incorrectly. I recommend that you read about window ownership to better understand the issue.
The correct solution to your problem is to show a modeless dialog. A modeless dialog allows you to interact with the other windows in your application. And that's exactly what you ask for in the question.
You show modeless dialogs by calling CreateDialog followed by ShowWindow. This MSDN article shows an example: Using Dialog Boxes.
If I recall correctly, you can either pass NULL instead of the handle to the parent window or change the dialogbox type in the resource editor.
That is an easy way to do it, however the following is certainly better - since having an unowned dialog isn't your best choice.
The point is that DialogBox() will create a modal dialog window, while CreateDialog does not. Modal dialogs disable the parent window.
From MSDN: A modeless dialog box neither disables the owner window nor sends messages to it.
That should solve your problem.
CreateDialog(hInstance, MAKEINTRESOURCE(IDD_WINDOW_INFO), hMainWindow, WindowInfoProc);
ShowWindow(hWnd, SW_SHOW);
In my application I have a CFormView with a CTabCtrl, I also have 4 CFormViews that are children of the main CFormView and that are shown/hidden when the user changes the selected tab.
However, I can't find a way to make the Tab Order to work properly. If the CTabCtrl has the focus, pressing the Tab key has no effect and if one of the child CFormView has the focus the Tab key will move the focus only around the controls inside the CFormView.
I tried changing the z-order of the visible child CFormView to be right after the CTabCtrl with SetWindowPos, changed the child CFormViews styles to WS_EX_CONTROLPARENT but nothing seems to work.
You've started out from the wrong implementation: you shouldn't make a CFormView with a CTabCtrl and then stuff more CFormViews into it. This isn't going to work right. Instead, you should work with CPropertySheet and CPropertyPage, where focus handling has already been taken care of. You will still be able to access the CTabCtrl owned by the CPropertySheet by calling GetTabControl(), but MFC will take care of the problems you've encountered.
Briefly: derive classes from CPropertySheet for each of the dialog windows you want to show (e.g., CConfigPage1, CConfigPage2). Create a Dialog resource in the Resource Editor for each of them, and do all of the other standard CDialog setup.
Next, derive a class from CPropertySheet (e.g., CProps), and (optionally) handle WM_SIZE and TCN_SELCHANGE.
Finally, derive a class from a CView descendent, like CScrollView (e.g., CViewMyAwesomeStuff). Then add member variables for the CPropertySheet and CPropertyPages, and handle WM_CREATE where you Add() each page to the property sheet and then Create(this,WS_CHILD|WS_VISIBLE) the property sheet.
Bonus: You can forward the CView::OnUpdate to each child CPropertyPage by calling GetPage() in a loop and calling a function on each of them, or you can send a message to each of them (use a user-defined message, like WM_APP+1). They can discover their parent's CDocument by calling GetParent()->GetParent()->GetDocument().
Okay, so I will admit I have no knowledge of windows API or even MFC.
I've got an error window popping up when things go hairy (illegal character in a filename string) and I want the error box to be modal.
For the life of me I can't figure out why it crashes when it hits doModal.
Here is the code where I think this can be fixed. This code is in the event handler of a button in the main window.
CDialog *BadFileD = new CDialog();
BadFileD->Create(IDD_STATUS, this);
BadFileD->DoModal();
Am I just being borderline retarded?
MFC dialog divides two pattern, modal dialog and modeless dialog.
(1) Modal dialog usage:
CDialog dlg;
dlg.DoModal();
(2) Modeless dialog usage:
CMyDialog *pDlg = new CMyDialog();
pDlg->Create(ID_DLG, this);
pDlg->ShowWindows(SW_SHOW);
As you can see, we need a new pointer, but do not delete it. So, you need to do the following in our CMyDialog class:
Add DestroyWindow() method in OnOk() and OnCancel().
Add "delete this;" in PostNcDestroy() method.
If you do not, your code may cause a memory leak. BadFileD is a class member, and you delete it in destructor. I suggest use Modeless dialog.
For display modal dialog you should use DoModal method only
CDialog *BadFileD = new CDialog(IDD_STATUS, this);
BadFileD->DoModal();
You can read remarks from article
If you desire to just display an error message, it may be that rather than creating your own dialog you can just use AfxMessageBox(). See Microsoft Developer Network - AfxMessageBox.
If you want to do your own dialog box typically with an MFC project you would normally:
create a dialog box template using the resource editor
create a class encapsulating the dialog box with the class wizard implementing the behavior desired
insert the code to create and display the dialog box into the appropriate place
However with a simple dialog box that requires no supporting class for complex behavior you can skip the step of creating the encapsulating class with the class wizard and just use CDialog directly.
One question that needs to be answered is the lifetime of the dialog as well as whether it is to be modal or modeless. A modal dialog box requires the user to do something for the application to continue past the modal dialog box. A modeless dialog box does not block the application the way a modal dialog box does. There is also a system modal dialog box style.
Since you say it will be a modal dialog then the lifetime will be short so the entire construction, display, and destruction will probably be in a series of lines of code. For instance in a CView class with a command handler displaying a modal dialog box you might have:
void CViewThing::OnCommandMenuItem ()
{
CDialog BadFileD(IDD_STATUS);
int iRetStatus = BadFileD.DoModal();
// check for status such as IDOK, etc.
// do whatever is necessary.
}
What the above does is create a dialog box using the dialog resource template IDD_STATUS and displays it as a modal dialog box. Since it is local object, when the variable BadFileD goes out of scope, the dialog box destructor will be triggered and resources cleaned up for you.
You can also have a modeless dialog box. In the case of a modeless dialog box you need to consider the variable lifetime because as soon as the variable goes out of scope, the destructor will trigger and the dialog box will disappear.
So for a modeless dialog box being used with some view class, perhaps providing a tool box of some kind, the CDialog variable will be a member of the CView class which is using it. After the modeless dialog box is created, it is displayed or not by using the ShowWindow() member function of the CDialog class (actually a member of the CWnd class from which CDialog is derived).
void CViewThing::OnCommandMenuItem ()
{
BadFileD.Create(IDD_STATUS, this);
BadFileD.ShowWindow(SW_SHOW); // display the dialog
}
and in the CViewThing class you would have a member variable CDialog BadFileD;.
Additional considerations
In all of the above examples we are not using pointers so that when the CDialog variable goes out of scope, either from exiting a member function or when the object using the dialog box is destroyed then the dialog box is as well. This object management is done for us.
One thing that you must take into consideration with a modeless dialog box is how to destroy it when you no longer need it.
Since a modal dialog box is usually a short term object, often created as a local variable on the stack, you normally just let it go out of scope to take care of everything dealing with destruction.
However the lifetime of a modeless dialog box requires that the DestroyWindow() method be used to destroy the dialog box when it is no longer needed. See Microsoft Developer Network - Destroying the Dialog Box.
A third usage scenario - embedding a dialog box
There is a third usage of a dialog box that sometimes comes in handy, embedding the dialog box into another window as a control.
In the above examples, the dialog box template specifies the WS_POPUP style for the dialog which is the standard style for a dialog box since the normal way that a dialog box is used is to display as a separate window.
However if you change the WS_POPUP style to WS_CHILD you can then embed the dialog box into another window as a control. You can remove the other style settings such as WS_SYSMENU, DS_MODALFRAME, and WS_CAPTION and remove the CAPTION line from the dialog template to further change the dialog box. So you will end up with something like:
IDD_STATUS DIALOGEX 0, 0, 435, 266
STYLE DS_SETFONT | WS_CHILD
FONT 8, "MS Shell Dlg", 400, 0, 0x1
BEGIN
LTEXT "this is some static text to display on this dialog.",IDC_STATIC,81,63,200,32
END
Then just use the resulting dialog box similar to how you would a modeless dialog box with ShowWindow().
If you need to reposition the embedded dialog box within its container window, you can use the SetWindowPos() method to do so. For instance the following would move the dialog box window within its containing window to be 20 pixels from the left and 10 pixels from the top of the containing window.
BadFileD.SetWindowPos(NULL, 20, 10, 0, 0, SWP_NOOWNERZORDER | SWP_NOSIZE | SWP_NOZORDER)