I need to understand the differences between windows main/mdi/child/dialogs.... how win32 messages should be propagated... why some messages are present in one type and not other...
There is reference information available here on the MSDN website. If you want more of an introduction or tutorial, then Charles Petzold's book Programming Windows is excellent.
Main window
The application's top window. It is flagged as the process main window and this information can be readily accessed by calling processes with the appropriate permission.
MDI (Multiple document interface) window
This is, typically, in an application main window and it contains a set of MDI Children. This is mostly a window class integrated with Win32 API. I believe it's not treated differently by the operating system as any other window class. Those are becoming extinct in favor of multiple SDI windows (Word 2007).
Child
This is a child window of any other window. Its position, visibility and mostly everything is dependent on the parent window. The children send notifications to their parents. A notification is a specific kind of window message.
Dialog
Dialogs provides easy child creation and input handling based on what 95% of dialogs need. Dialog functions in the API let you create a window and its children using compiled templates in the PE file (.exe). The message handling is also slightly different since you are working mostly with notifications from children.
The main difference with dialogs is when you are using a modal one. The creation call will block until the user closes the dialog. This can make UI updating a little tricky in some situations.
Im not a windows developer, but heres what I understand:
main window - toplevel container which you can active/see in the taskbar.
dialog - little box locking (if modal) your window, not seeable in the taskbar. Mostly used to display message to the user.
mdi (Multiple Document Interface) - Not directly a window but more a simple container for storing child windows. Each child window can be maximized/minimized/closed inside this container, but you wont find any of these in the taskbar.
http://en.wikipedia.org/wiki/Multiple_document_interface
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Our agency has a Java web application that uses a third party Java applet as a TIFF viewer. In this application javascript spawns a separate window (and yes, it must be a separate window). We are currently using an in-house ActiveX control so that the HTML window can have the window state, window size and position, and screen device presisted and restored via localStorage. Our agency is IE11 only so for now using it is not a problem. It's embedded in the page and operates on the "containing window".
This control was made many years ago in VB6. It appears that Visual Studio doesn't support the creation of ActiveX controls, and I don't personally have the knowledge or skill to create one another way.
Please do not suggest the HTML DOM window and screen objects! Most answers I've searched for just refer to these! They can't get the entire browser window size (viewport + chrome + toolbars + titlebar), nor does javascript have any idea about Windows-specific things like window state and screen device (it's always the OS primary screen). I understand the HTML DOM can't be tied to anything OS-specific in order for it to be implementable on multiple platforms.
Up until now this control has worked pretty well - you can, for example, maximize on a given screen and restore the window to the same screen. But I realize that ActiveX won't be supported forever and it's IE only...It seems to me, though, that the need for such functionality can't be totally uncommon. I'm guessing that some may suggest that the application UI should be changed so that this is less of a problem - but being able to put the viewer on a different monitor from the application, and having that window be restored exactly to it's last position is important to us. I do understand that if you reuse that window the user only has to position it once, but we'd rather not require this of the user.
Question: are there any alternatives to interacting with the win32 API other than COM/ActiveX ? Are there any other methods of accurate window persistence that can know about screens other than the OS primary, and maximized/minimized/normal windows) that use something other than the Win32 API?
So, I have a dialog based application using pure WinAPI. There is a main dialog, and then multiple other dialogs that are toolwindows. These toolwindows are meant to free-float around, the user can drag them, hide them, and show them, but they have no taskbar entry. This is what I intended, but the problem is, when I switch from the main window to a different application, then click on the taskbar entry for the main window, the main window will show up, but the toolwindows will not. They stay hidden behind the main window and sometimes windows of other applications, and you cannot use them until you move all of the top-most windows and hunt down the toolwindow.
So, what I'm trying to do to work around this is, when the user restores the window from being minimized, I want to enumerate through all of the tool windows and bring them to the front, maybe by calling SetActiveWindow().
But what message gets sent when the window is restored? I was thinking WM_SHOW, or WM_RESTORE, but they don't exist.
Another question, and if you answer this the first question is irrelevant because I will no longer need to use that workaround: Is there a better method of bringing all tool-windows to the front?
Give the tool windows the WS_POPUP style (and not WS_OVERLAPPED), and make the main window their parent (strictly it is their owner window). That way the tool windows will remain on top of the main window. This may (or may not) be what you want.
The naive answer to the question is to listen to WM_SIZE and respond to a wParam value of SIZE_RESTORED.
The other obvious possibility is to make all the tool windows be owned by the main window. So long as you are happy for the tool windows always to be on top of the main window, this will solve your problem. The owned windows will be hidden when the owner is minimized, and re-shown when the owner is restored.
Learn more about ownership in the MSDN topic on Window Features.
How do i make the common File dialogs App modal using Common File Dialog API ? The dialogs come up modal with respect to the owner window. I want to block all the process' windows when a file dialog is up. In my current code, I am disabling all windows belonging to the app except the dialog parent and when the dialog is closed I enable them again. There should be a better/easy way of achieving application wide modality with Common File Dialogs. Please let me know if there is a standard solution for this.
Manually disabling and re-enabling is the only way I know of in Windows.
The traditional model for Windows applications is to have a single top-level window per instance. (Remember MDI apps?) Of course, there are exceptions, and many apps have always had floating tool palette windows. Nevertheless, the disable-the-parent model works for the lion's share of applications, and it's possible for many-window apps to do what you're doing with manually disabling the extra windows. Thus there isn't much demand for a more general solution.
If you wanted to re-architect things, you could have a master window that owns all the other top-level windows, and make the modal window use the master as a parent, but then you'd have to solve other problems related to the task bar, z-order, and positioning of the modal window.
I'm currently working on a Win32 program which requires a main window containing many child window controls - buttons, listviews and so on. I believe the standard way to build such a window is to first call CreateWindow for the main window, then again for each of the controls.
As an easier option, I'm considering designing the main window using the resource editor's dialog box designer, then using CreateDialog to build the main window in one go.
By using a CLASS statement in the dialog box template, I should be able to get the main window to use a custom window class (and hence a custom window procedure) and thus avoid the window having any dialog-like behaviour. An example of this technique can be found in Charles Petzold's "Programming Windows": the HEXCALC program in chapter 11.
Are there any downsides to creating my main window in this way? If so, what are they? If not, why is this approach rarely used?
You don't get control of your main window message loop - the dialog manager handles it for you. On the other hand, the dialog manager handles keyboard accelerators, tab ordering and a number of other effects.
You'd be surprised what you can do with a standard dialog box - the windows volume control is implemented with about four different dialog boxes - it has a frame dialog box which in turn host hosts a tray window which in turn holds volume control dialog boxes, one for each app volume.
The only downside of CreateDialog I know of (as compared to repeated CreateWindow, not talking about some heavyweight framework, just Win32 vs Win32) is that dialog resources position child windows using dialog units. So the layout is dependent not only on DPI, but also on the user's theme settings (choice and size of font).
If any of your controls need to have fixed sizes in terms of pixels, you won't be happy with the dialog-provided positioning and will need to go through and move all the child windows after the fact.
So yes, you can use CreateDialog as a shortcut for creating a bunch of windows with specified classes and styles. But no, you can't do your layout in the dialog editor.
OTOH, you could store the DLU <-> pixel conversion used on your design machine, and then learn enough about parsing the DIALOG resource internal format to pull out the positioning information, then convert to pixels and correct the positioning in more automated fashion.
You will be able to have the full control over your window, even if it was created with CreateDialog.
Normally, when you create your own window (of your class), the window procedure used is the one that you registered with the class. OTOH windows created via CreateDialog will have the dialog standard window procedure (DefDlgProc), which will mostly invoke your supplied "dialog handler".
If you want to have full control of all the messages you may replace the window proc of the newly created window right after its creation. Just call SetWindowLongPtr with GWLP_WNDPROC parameter. Still, you may do the auto processing of some dialog-specific things by calling IsDialogMessage within your procedure.
There is no downside whatsoever.
Why is it rarely used? Because:
People normally use DialogBox instead, since that is easier for simpler cases.
For more complex cases, people use things like MFC or ATL (or some external library like GTk or Qt), and don't bother with native Win32 graphics.
There are no downsides using the Windows SDK, internally libraries like MFC use the Windows SDK .
People tend to use libraries like MFC over Windows SDK, as libaries have the readymade stuff. However Windows SDK calls are faster than library calls, so in some situations developers call Windows SDK directly .
CButton btnOk ;
btnOK.Create(_T("Press Me"), WS_CHILD|WS_VISIBLE|BS_PUSHBUTTON,CRect(100,100,300,300), pParentWnd, 1);
is similar to the following code ,
HWND hWnd = CreateWindow("BUTTON","Press Me",WS_CHILD|WS_POPUP|BS_DEFPUSHBUTTON,100,100,300,300,NULL,NULL,GetModuleHandle(NULL),NULL);
ShowWindow(hWnd,SW_SHOW);
I am debugging an application which, in its message loop, calls IsDialogMessage(). Occasionally, IsDialogMessage() never returns (where never is an interval greater than 1 hour). Based on the symbols for user32.dll available from Microsoft's symbol server, it appears to be stuck in GetNextDlgGroupItem() (or an internal variant of the same), iterating over some set of windows.
The application is multithreaded and frequently receives notification of external events, which arrive as DCOM calls. I suspect that such a call is handled incorrectly in a way that corrupts some window state. If I can learn what sort of state corruption might cause an infinite loop in IsDialogMessage(), I think I will be more easily able to identify the source of the corruption.
I know this is old, but answering for posterity since no one here mentioned it.
More than likely what is going on is trouble with the windows manager determining where to forward a message. If you have a hierarchy of windows, as you probably do, then you need to ensure that non-top-level windows that contain controls themselves must have the WS_EX_CONTROLPARENT style set. If it is a dialog, you use the DS_CONTROL style. The presence of these flags modify the behavior of IsDialogMessage; they identify a window as having its own controls which can receive focus and handle tab order, etc, rather than just being a control itself.
For example, if you have a main frame window, which has a child window with WS_EX_CONTROLPARENT, which has a child window without WS_EX_CONTROLPARENT, which has a child window that has focus, and you hit TAB, you will likely encounter an infinite loop at the same place you mention.
Setting the second child's extended style to include WS_EX_CONTROLPARENT will resolve the issue.
Are you maybe disabling controls (using ::EnableWindow()) without checking first whether that control has the focus? If yes, then the focus gets lost and GetNextDlgGroupItem() gets confused.
Another reason this can happen is if you reparent a modeless dialog. At least this can happen with wxWidgets...
I've made some investigation, trying to answer this question. But only in situation, when parent window is in native MFC project and child is a managed C# Windows Forms. If you have such situation, then you may try 3 resolutions:
Run MFC dialog message loop on Windows Forms side. Here is more info: Integrate Windows Forms Into Your MFC Applications Through C++ Interop
Create 2 threads: one for Windows Forms dialog and one for native dialog. Here you can create dialog in Windows Forms, then with SetParent() set it's parent to native dialog. But be ware: if you add TabControl to Windows Forms, than hang with "IsDialogMessage() never return" will occur.
Make a wrapper for Windows Forms dialog to use in native project. For ex., wrapper may be WPF, see here: Windows Form as child window of an unmanaged app
I've taken information mostly from: http://msdn.microsoft.com/en-us/library/ms229600.aspx
And the temporary cure can be to change focus behavior. For example, disable them, or SetFocus() to parent or child windows only. But I strongly recommend to investigate the real reason, why IsDialogMessage() never return in your case.