I just started the GUI development, i had started on C++Builder but i switched to Visual Studio for differents reasons. But in Visual Studio, i've got a big problem :
In the GUI development interface (rc file) i can create buttons and place it, but i can't change there names. The name for all of MFC components i placed is initialize to a default name which i can't call and i can't change the property by the properties interface, i can change the Text, for change the Label of the Button, but not the name...
It's very incomfortable because by that i can't call my buttons for do anything, i have the same problem for Listboxs, so i can't modify my list because i can't call there
I just want to modify access my component by my c++ code for modifying this component
enter image description here
Thank for your help !
The MFC way of doing event handling is a bit more elaborate.
After the control is created on the form in the designer, an ID is generated ("IDC_BUTTON1" in the attached screenshot).
This is the ID that will be used for accessing this UI control from the code.
All this can be done via the designer also as shown in this article.
Basically, in the background this generated ID is put in a 'message map'
(more about message maps here).
In short 'message map' is used to specify what action needs to be performed when a certain type of action is done on the UI control by the user.
For, example if the button click is to be handled then in code:
the message map would look like:
BEGIN_MESSAGE_MAP(CSurface3DView, CView)
ON_BN_CLICKED(IDC_BUTTON1, CallMyFunction)
END_MESSAGE_MAP()
'ON_BN_CLICKED' is a predefined event macro.
The 'CallMyFunction()' function has to be declared with 'afx_msg' in the class. Besides please, have a look at data exchange mechanism as well. This know-how about data exchange will come in handy going forward.
Related
I am working on a Windows application using MFC and Visual Studio C++ 17.
I have multiple tabs in the application, one of which is currently implemented using CListBox and needs to be reimplemented using CCheckListBox.
CCheckListBox is a child class of CListBox.
I have a vector of unique CString's I want to display in the box.
To start simple, I tried making the tab with CListBox and by using CListBox::AddString(), this worked exactly as I wanted it to. It sorted the strings alphabetically, and automatically added a scroll bar on the side when the vector had too many CString's to display all at once in the list.
However, when swapping the CListBox variable to a CCheckListBox variable, I have come across the error when I press run along the lines of:
Debug Assertion Failed! ..... \mfc\winctrl3.cpp Line: 588
I found this GitHub link that has the winctrl3.cpp file and on line 588, there is a function called OnLButtonDblClk which is somewhat explained here.
The trouble is I am unsure of how to swap a variable from a parent class to a child class. Is it so different for Windows classes? In the courses and programs I have taken and written in the past, switching from a parent to child variable was straightforward but this is quite the opposite !
Any help is appreciated, thank you in advance ! :D
There is no assertion in line 588 of the source file in your link. That github upload dates back to 2014. Why not search the winctrl3.cpp source file in your own Visual Studio installation instead? In my own installation, it is in function PreSubclassWindow() and there is indeed an assertion there:
// CCheckListBoxes must be owner drawn
ASSERT(GetStyle() & (LBS_OWNERDRAWFIXED | LBS_OWNERDRAWVARIABLE));
That is the CCheckListBox must be owner-drawn. Find the CCheckListBox constructor code above, you will notice that it calls the CListBox (parent-class) constructor, applying either of the two owner-drawn styles. Instead, the CListBox constructor calls CWnd::Create() with the "LISTBOX" Windows Class-Name as a parameter. That is, it seems to be a MFC-implemented control, overriding the CListBox class, with an owner-drawn style. There is no mention of a native "Check-ListBox" class or style in the Win32 documentation either. Also the CCheckListBox documentation (in the link you posted) clearly states: CCheckListBox is only for owner-drawn controls because the list contains more than text strings.
Therefore:
If you are creating the control using a resource script, add an owner-drawn style (eg LBS_OWNERDRAWFIXED) to the control (or set the Owner-Drawn property in the property editor).
If you are creating the control programmatically make sure you are calling the CCheckListBox constructor, not the CListBox one.
Not sure what you mean about the scroll-bar (and why you mention it), doesn't the list-box display a scroll-bar automatically (WS_VSCROLL style - or property), do you have to do something on your own?
EDIT:
Forgot to mention, if you are creating the control using a resource script use the Class Wizard to add a member variable (of "Control" type, not "Value") to the dialog class. The new variable must be of type CCheckListBox (MFC class). This will subclass the control. If the old project already had a CListBox member variable change it to CCheckListBox.
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.
I've been trying to implement a file dialog into my C++ application for a while now, and I achieved good success with the code described in this article (It is german, but the code should be understandable):
https://msdn.microsoft.com/de-de/library/windows/desktop/ff485843(v=vs.85).aspx
However, using this code in my window class, which is a CDialogImpl, I just can't find out how to make this file picker modal. If I use this code, I can just spawn multiple file picker.
Of course, I could just keep track of the state by adding a member variable representing the state, but it would still not solve the problem of being able to click around in the main window while the dialog is opened.
Is there any way which would allow me to make this window modal? I've been trying to scan through all available methods, but I couldn't find anything. I didn't find any flags which could be passed in the creation, neither any options which I could set after creation.
Any help is appreciated!
The example you link to is very simple and has no UI other than the file dialog. Your program is more complex, having a window from which the file dialog is invoked.
You need to provide an owner for the file dialog. When you do that the owner is disabled, part of what makes the dialog modal. Failing to pass an owner means that the other windows are not disabled and so still respond to user input.
The example code provides no owner, but since there are no other windows in that program, that is benign. Modality is only meaningful when there are multiple windows.
So, to solve the problem, pass the owner, the handle of your window, to the Show method of the file dialog.
Disabling owner windows is one of the key parts of a modal dialog. You will find that any API for modal dialogs expects you to specify an owner. Get into the habit of expecting to provide that ownwr window, and looking for the means to do so.
In ResourceHacker, when you open an executable (windows), you can see identifiers associated with dialogs. Does anyone have an idea from where they come? I mean, how can I do the same in my C++ program to get the ID from a HWND?
BTW, GetWindowLong(hwnd, GWL_ID) returns 0.
Thanks
The GetWindowLong(hwnd, GWL_ID) returns the identifier of a control in a dialog, but it cannot be used for the dialog itself, because dialogs simply don't have identifiers.
The identifiers associated with dialogs are actually used to refer to the resource blob itself, not to the window. They are used to create the dialog (see CreateDialog().
Once the dialog is created there is no connection to the original template or to that identifier. Actually there is no use for that ID, the dialog is simply identified by its HWND. Note that you can create several different dialog using the same dialog resource.
These identifiers are assigned (usually) sequentially by the resource editor, or manually if you create the resources by hand.
For more insight on the topic you can read about the CreateDialogIndirect() function, that creates a dialog without using a resouce.
Here you find a good answer:
http://blogs.msdn.com/b/oldnewthing/archive/2005/07/08/436815.aspx
It's like asking, "Given a plate of food, how do I recover the
original cookbook and page number for the recipe?" By doing a chemical
analysis of the food, you might be able to recover "a" recipe, but
there is nothing in the food itself that says, "I came from The Joy of
Cooking, page 253."
So the answer is that there is no way provided by Microsoft to obtain the dialog ID. They could have easily stored it anywhere to make it available, but they did not.
But there would still be a way to do it, although it is not bulletproof. You could:
1.) Get the creator file of the dialog via GetWindowModuleFileName()
2.) Load this Exe or Dll via LoadLibraryEx(..., LOAD_LIBRARY_AS_IMAGE_RESOURCE)
3.) Enumerate all RT_DIALOG resources in the Exe or Dll via EnumResourceNames() where the dialog ID is in the name: ResourceName = MAKEINTRESOURCE(IDD_DIALOG_ID)
4.) Create each enumerated dialog invisibly via LoadResource(), LockResource(), CreateDialogIndirect() but without showing the dialog with ShowWindow().
5.) Enumerate the child controls in each dialog via EnumChildWindows() and compare them to your dialog.
6.) Release all handles and destroy the dialogs.
It is not very probable that there are two identical dialogs in a Exe/Dll file. But the problem is that in WM_INITDIALOG the programmer may eliminate (destroy) or add or modify child controls. So your search algorithm would have to be fault tolerant. This would be possible by counting the congruency between each dialog from the resources and your dialog. You could count for how many child controls the ID (GetDlgCtrlID())and class name (GetClassName()) match. (e.g. Class="BUTTON" and ID = 311") While a programmer can easily change the text of a control or move it around, changing the ID is not very probable and does not make much sense and changing the class of a child control is even impossible.
As I said: It is not bullet proof, but you will find the ID of the resource that has most probably been used to create the dialog.
Be aware that not all dialogs come from a Microsoft resource.
They can be created by a GUI framework that uses its own type of templates. In this case you will never find the Dialog ID because it simply does not exist.
I'm turning mad with a little problem with Visual Studio 2008 and MFC. I'm working on a project actually and I'm trying to create an SDI Application. Right, now I want to add a dockable DialogBar. Well, the first time I added it with the resource view, I could create the bar without problems.
But... I want to add some controls like a couple of ListBox, buttons and so on. The program doesn't allows me to create member variables for these controls. The option appears in grey.
Searching a little, I found that it's mandatory to create a new class derived from CDialogBar and "enhance" it with the Message handler and so on. I've been reading some tutorials and it didn't work for me.
Can you please help me? I'm starting to get nervous, the use of dialogbars is mandatory in my design and I've never implemented them before.
Thank you very much, and sorry for my poor english.
You can add a control member variable by hand instead of using the wizard. All it takes is a call to DDX_Control in the dialog bar's DoDataExchange function.
But CDialogBar-derived classes do not handle control clicks. The CDialogBar class forwards all of those messages to the dialog bar's parent window. So be prepared to add the message handlers to the parent (usually CMainFrame).
For learning purposes you might try creating your dialog bar as a CDialog first, to see the proper code lines and message map entries supplied by the wizard. Then you can copy/move these details as appropriate into your actual code project.