I am creating a dialog based application, I found there are two components, which are dlg and app.
My question is, what is their different and if I want to write back end logic for the application, which file I should write to for better practice ?
My back end logic means:
e.g: creating an application receives input from two text boxes and sum them up
my back end logic means the function to sum up two variables.
The application (CWinApp) is the outer container, that contains all application specific stuff. The application object is a singleton.
The CMyDialog class carries out the UI and all actions belonging to one dialog.
Because an application may have more than one dialog class, you are not restricted to have only one dialog. But you always have only one application object.
So your logic should all be located in the dialog class.
The dialog and the application may exchange results and data. The normal logic is to copy the data from the application into member objects in the dialog. Launch the dialog. After the dialog is successfully executed the values are copied back.
Related
OK, so a noob question here: How do you code this functionality that browsers have for example? You open a chrome browser for example and you can open multiple tabs open. Then you can move one tab out of the window and it becomes another window, having its own separate process. Then you can drag that tab into another window and they become one frame? Similar to docking in windows applications, but how do you do it with executables?
Windows-specific answer, though I think other OSs work pretty much the same: the HWND handle that you get for a window is global. If you send its numeric value to a different process, that process can use it to do things with the window: get its information, resize it, even draw on it. What it can't do is replace its event handler function.
To get process separation like browsers have nowadays, the key is to create a container window and send the handle to the child. The child then creates its own window as a child of the container. The child window simply fills out the entire content area of the container.
This way, the content process is contained within the parent's window, but can handle events.
Now, if you want to drag out a tab into its own top-level window, the parent process creates a new top-level window with all the UI inside, and then re-parents the content container to this new top-level window. The content child follows along.
I can't tell you how to code it, you should search the feature inside the chromium code to know how it's coded but I can tell you how it works:
Inside chromium every tab, extension, utility, etc is a process, each one of these processes is child of the "Browser" process, the "Browser" process manages everything (creating new windows, opening new tabs, closing tabs, destroying windows etc) so, for example, whenever you open a new instance of chromium you are telling the "Browser" process to create a new tab and put it inside a new window.
Every window is managed by the "Browser" process and every tab is managed by a process that is child of the main process.
Now to reply your question: when you drag & drop a tab outside a window you're triggering an event that is caught by the "Browser" process which then create a new window and assign the tab to the new window.
Those informations should give you a hint on how you could develop this feature yourself.
If you want to know more about the chromium architecture I suggest you to read how chromium is designed at https://www.chromium.org/developers/design-documents
I searched on the forum and I don't find a solution for my issue. So I hope you can help me :)
I work on a personal project for SFC designing (Sequential functional chart) and I'm working with visual studio in SDI(I'm using MFC library). If you see the "design" of an SFC you can see the different elements needed to compose this. So you can find Step, Transition, and more. If I take a step for explaining my issue, after double click on the step a popup dialog is opened with the elements to define this step (actions on this step, and more). The issue is here, I can't see two or more step elements at the same time. I want to reuse the existing concept on other software, see this.
Step close
Step open
Dialog to add
My question is, how I can implement a dialog with my graphic element in mainframe (In this case, a step)? I don't know how I can insert a dialog with my element, I think I need to use CFormView, but I don't know.
This dialog needs to be resizable and reduce directly by the step graphic.
any idea?
Thank you in advance! Sorry for my English ..
Sorry, I think my request is not clear .. (Thank you for your answer)
The context, it's an SDI application with the Document/View architecture. Actually the view is derived from CScrollView.
So, in the document class, you have the different lists of components for make SFC (Steps, transitions and symbols ..). I'm working today on Step element.
The user inserts a new step, the step is draw on the view like this :
enter image description here
And now the user want change the events on this Step, for this after double click on the step the events editor is opened at right of step draw, like this :
enter image description here
For this, I've created a new dialog resource and create the class by wizard in CForwView derived class. In step attribute, you can find one instance of this derived class (The derived class of dialog).
But this doesn't work correctly, I think my method is bad. At the first try, I have sent the pointer of the current document to the "CFormView::Create" function for having the "Save" button active with the focus on the FormView. But after destroying the step, the instance of FormView is destroyed and the document with the instance of formview ...
No problem, you can use "Create" within CCreateContext a null pointer. But with the document or without I have a lot of problems (graphic design not correct in FormView, regularly (not systematic I have assert fail on Proc exchange (for differents reason)). But the "concept" is good, the editor follows the draw if I scroll, I can open or close the editor at any time and on any elements.
For the old capture, it's my SFC designer "model". My application is a complement to this application, so I want a similar design. I don't know how work my model application ..
On my application all is draw by MFC GDI, I don't use ActiveX or other tools.
So what is the correct way to implement one instance of editor by instance of step ?
For the implementation on this FormView I have :
- Make new dialog in ressource
- Create a derived class of CFormView with the created dialog
- Add one instance in attributes of Step element
- "OnDbClickOnStep" -> Call "Create" with the good position / size, pointer of mainview (in my case the CSrollView derived class)
- Done, FormView inserted in a mainview, I can edit my step events.
? Not done, I lost save button and other function linked to the document with the focus on a control in FormView. The app want a document with this view, how to override this ?
? Error in Proc exchange, for different reason...
You have an idea ?
You normally don't draw anything in the "main frame" (or the "MDI clild frames", in the case of a MDI application), this is done by the library, and imo sufficiently so. You display your data in a CView-derived class.
CView is the base class of all other MFC view classes. It's a simple graphical class - you need to paint it yourself in the OnDraw() member.
CScrollView is a descendant of CView, adding scrolling functionality (scroll-bars are automatically displayed if the scrollable area is bigger than the visible window area).
CFormView is a descendant of CScrollView, displaying a dialog resource-script, containing "controls" (edit-boxes, check-boxes, images, ActiveX etc).
As in your case the "controls" won't be initially known (except maybe for some few special cases) and rather programatically created, the resource script will most likely be empty, so using either CFormView or CScrollView will basically be the same. I would suggest starting with CFormView, and "downgrade" it to CScrollView if CFormView is not necessary or causes you troubles.
What are those "Step" items shown in the pics? ActiveX controls, child dialogs maybe? These work best as child controls on a dialog window. Are they already implemented, or they are just pics of some other software? Btw ActiveX is a way to define controls that can be used in other projects too, without having to include them in the project source.
Currently I am writing a C++ Qt GUI standard (i.e. via Qt Creator) application.
Basically, what I am trying to do is an application, which operates the following singleton classes:
a MainWindow class, which is responsible for the core logic;
a ServerWindow class, which is responsible for the server connection;
a User class, which is returned (in form of a pointer) by the ServerWindow class after successfull authentication;
a Data class, which is initialized with the data, recieved via ServerWindow upon user authentication.
The algorithm is:
Construct a MainWindow and create a Data class; it also holds a pointer (nullptr at this step) at the current user.
When the constructor has finished, the ServerWindow (derived from QDialog) is executed (via Qt delayed connection). At this step the MainWindow is frozen and set invisible, untill the ServerWindow emits one of the signals (logged, fail). The ServerWindow has a modal mode flag set.
When the ServerWindow is done, a pointer to the current user is passed to the MainWindow. The ServerWindow also knows about the Data class and initializes it.
The main problem is that at step 2 the application icon in the taskbar (I use Windows OS) is not shown. When the MainWindow is "offline" (i.e., not shown, invisible via setVisibility(false)), there is no icon. It is highly annoying, especially if there is a bunch of other applications open. So that, my question is: what can I do to make ServerWindow create an application icon in the taskbar without MainWindow being shown?
The additional, by-the-way question is about possible application architecture remastering. I cannot find any books in my small library about similar applications designing. Frankly, I cannot even figure out, which words I should pass to the Google search line. Any advice?
Preliminary, thanks for any answers!
I am coding a test application for a windows CE device. This is the first time I am programming for a handheld device. I use MFC VC++ on Visual Studio 2008. I have found that there are many restrictions in the controls and what I could do with them when running the program on a handy versus when I run a similar program on a desktop computer.
Now, the device I am currently deploying my test program to, does not have a touchscreen and has few extra keys other that the numberpad 0-9 keys. So, I have to do with a simple GUI that uses keydowns to call specific functions like add, edit, delete etc... It also forces me to use separate dialogs for each of these functions so as to avoid unnecessary mouse cursor usage.
This leads me to my current problem: The 'ADD' dialog of my test app adds some user data to a CListCtrl that is on the 'MAIN' dialog. The 'EDIT/DELETE' dialog is to allow the user to select the desired data from its own CListCtrl and press the "ENTER" key, which thereby deletes the selected data from the 'MAIN' dialog's CListCtrl. Thus, both the main dialog and the 'EDIT/DELETE' dialog have CListCtrl with the exact same data. So, instead of having to use 2 separate list controls and using loops to copy the data to and fro among them, is there a way in which i could use the exact same CListCtrl (one and only one instance of the CListCtrl exists), but display it on 2 separate dialogs? This would remove all the copying code, as well as halve the amount of data in memory.
I tried passing a pointer to the MAIN dialog's CListCtrl to the 'EDIT/DELETE' dialog in hopes that I could redraw the control there, but in vain. I could call the RedrawWindow, RedrawItems commands, but they seem to have no effect in the 'EDIT/DELETE' dialog (I think it is because the control itself is not present on the edit/delete dialog). Any other suggestions?
You could temporarily change the parent of the ListCtrl using CWnd::SetParent to the EDIT/DELETE dialog, and set the position with CWnd::SetWindowPos to where you want to have it. When the dialog gets closed, set the parent back to the MAIN dialog.
I have developed a MFC ActiveX control, that displays a graph using data retrieved from Kepware OPC Server using OPC Client. OPC Client code is part of ActiveX control code. The OPC client is launched in a separate thread from main control thread. The control works well when there is only one instance of it on the MFC dialog. However if I add another instance of it on same form, the curve on the graph starts malfunctioning. From the logs I can see that Control app class which is ultimately derived from CWinApp is instantiated only once. Any ideas why it is messing up? Are any global variables being shared between two instances? I am using Visual Studio 2008.
If your ActiveX control is located inside a DLL this DLL is always loaded once into the process that uses the ActiveX control. So it is normal that you only have one CWinApp object even if you have multiple controls.
So you need to design your object in a way, that global data inside the DLL doesn't affect the behaviour or data inside a control instance.
I suppose that you have some global data, that is used by the first control. And when another instance is created this global data is modified by the second instance and the first instance shows wrong data or misbehaves.
All state of such an ActiveX must be located and allocated inside the object.