I'm starting my journey with C++ and i need help with passing data to my forms objects.
I wrote simple bot (dll project) which is injected into game and doing some stuff. Now i want to add GUI for it. So i added Forms to my project. All working well but i dont know how to pass data into my active form window from outside of form class.
For example. I have a function that receives data from game and i want to pass them to my datagridview. I tried something like that:
In Forms class i added a method to fill datagridview:
void sendToGridView(char* data,PacketDirection direction)
{
this->dataGridView1->Rows->Add(PrintPacket(data, direction));
}
In my function (outside of Form class) i try to call this method:
MainForm mf;
mf.sendToGridView(lpMsg, Recv);
but it doesent workBig THX for any tips, hints and sugestions.
I temporary resolved this issue by creating class
ref class FormCaller
{
public:
static MainForm^ form;
};
And on the Form side public getters and setters
example of calling from functions:
FormCaller::form->sendToGridView(packet, Send);
Related
I'm trying to figure out the best (cleanest) way to structure some code in C++ for an application I'm building. I think MVC makes sense as the way to go, but after a fair amount of research I'm not totally clear I'm doing things the right way.
Here's an example to illustrate my question:
Model
I have a class which contains drawing data called Canvas. An example function, used to clear the current contents of the canvas, is ClearCanvas().
Ultimately, I want a button in the interface to be able to call this function and clear the canvas.
Controller
I have a controller class for the canvas: CanvasController
The controller creates and then holds a reference to a canvas object: CurrentCanvas
The controller also creates the view: CanvasView and then sets a reference to itself on the view: CurrentCanvasView->SetControllerRef(this);
View
The view is made up of a series of nested classes that define the UI. For example, the hierarchy leading to the button in question might be something like this:
CanvasView
-VerticalBox
--HorizontalBox
---Button
During the view's constructor, a reference to the controller is passed from the view to all interactive elements, eg. NewButton->SetControllerRef(this->GetControllerRef());
Button Pressed
So now when the button is pressed, it can function like this:
void ClearCanvasButton::OnButtonPressed()
{
Controller->CurrentCanvas->ClearCanvas();
}
So my general question is: (1) does this seem like the right way to be doing things, or badly structured?
Also (2): Should the controller be encapsulating the canvas functions, for example:
void CanvasController::ClearCanvas()
{
CurrentCanvas->ClearCanvas();
}
Such that the function on the button could simply be:
void ClearCanvasButton::OnButtonPressed()
{
Controller->ClearCanvas();
}
I'm just not sure whether it's correct to essentially be passing down a reference to the controller to all elements of the view which ultimately want to change the model, or whether there is a cleaner way.
Apologies if the question has been asked a thousand times in a thousand different ways, I have been searching around trying to understand this.
You don't need a class ClearCanvasButton, if your Button class contains a member like
std::function<void()> onButtonPressed;
or similar, rather than
virtual void onButtonPressed() {};
You then pass a lambda that references the controller
CanvasView::CanvasView()
{
// make the widgets
Button.onButtonPressed = [Controller](){ Controller->ClearCanvas(); };
}
I would like to use call a C++ function from Qml in the following way:
Item{
id: qmlItem
function loadModel(dataModel)
{
// setup my listview
}
MyDataModel{
id: model
}
Button{
onClicked: {
cpp.addValues(model)
loadModel(model)
}
}
}
Now in C++ I have the following function:
void myCpp::addValues(MyDataModel* model)
{
// here I would like to add items to my data model
model->addItem();
}
Now this would be possible if the model was passed as a pointer, but I am not sure if this is the behaviour of C++/Qml interaction. Would what I wrote work or there is another approach I need to use?
EDIT: I have compiled the program and it works fine. However, I would like to know what is going under the hood. I mean does QML sends parameters by pointer? Would the same approach work with a JavaScript array (instead of MyDataModel)?
Actually, if you want to use model for ListView which is passed from C++ you should look at the QAbstractItemModel or QAbstractListModel(maybe better and easier for your case) class from which you inherit and create your own model to use in the qml. To subclass QAbstractListModel from you'll at least need to reimplement rowCount() , data() methods, also you can reimplement insertRows() and removeRows() methods to dynamically add/remove data from model (which will also update the view automatically).
You should look up the http://doc.qt.io/qt-4.8/qabstractlistmodel.html or http://doc.qt.io/qt-4.8/qabstractitemmodel.html
. Also, there were some easy examples in qtcreator on how to implement this kind of model
I am new to mfc, so I don't know if I will explain my problem correctly but I'll try.
So I built a puzzle game in mfc, and I want to implement high score system. When the game is over, the dialog pops up, where you put your name, and name is written in the external txt file. So, I have Dialog class, where I implement stuff about putting in your name, and sending it to a txt file, but the problem is that I can't access the info about the score, which is stored in the ProjectDoc class, so I can't link the name of the player and the score.
So the question is how to access files from ProjectDoc class from dialog class.
The solution offered by IInspectable and thomiel works great if you have one (or a few) parameter.
Another extreme would be to pass a pointer to the Document and let the Dialog pull whatever it needs out of it, but that would violate "need to know" policy.
I would suggest to define an interface (abstract class) IHighScoreProvider with required accessors, for example:
class IHighScoreProvider
{
public:
virtual int GetGameScore() = 0;
virtual std::string GetPlayerName() = 0;
};
Then derive your Document from it and implement those methods. And pass that interface pointer to your dialog.
Submit the score as parameter in the constructor of you dialog class:
CHighscoreDlg::CHighscoreDlg(int score)
{
m_score = score; // store in private class member variable
}
...
...
void CPuzzleView::EndGame()
{
CHighscoreDlg hs(GetDocument()->m_gamescore);
hs.DoModal();
}
I wasn't really sure how to search for this question.
I'm doing an embedded system design with the following scenario.
I have a main application class that needs to create a bunch of hardware interfaces such as a keypad, display, communication ports, etc... a whole slew of stuff
Now I have all these objets in the main application that I can use which is great
The application class contains a few sub classes that it can go into and stay for a while. One example is a menu class that it enters and runs inside that class until the menu is closed
I need the menu class to also interact with a lot of a hardware objects that were created at the application level
What is the best way to go about this without using global variables? Is there a good solution to this problem?
I could pass each object into the menu class, but I don't want to create a constructor with 20 arguments. My current solution is to put all the objects into a structure and pass that structure into the sub-class constructor. That way they also have access.
The part that bugs me about this approach is that I have to define the structure outside of the application which I don't really like. Something just keeps telling me it's not the best solution.
Open to any suggestions.
Presumably, there is ONE keypad - thus only one "Keypad Interface Object", right? Similarly with Display [ok, there may be two displays, but still].
So my suggestion would be to have a registration and a "container" that holds the registered interfaces something like this:
class KeyPad
{
public:
int getKeyPressed();
};
class Display
{
public:
OutputText(std::string msg);
};
... bunch of other stuff ...
class HardwareRegistry
{
priviate:
Keypad *keypad;
Display *display;
static HardwareRegistry *myself;
public:
Keypad* GetKeypad() { return keypad; }
Display* GetDisplay() { return display; }
void RegisterKeypad(Keypad *akeypad) { keypad = akeypad; }
void RegisterDisplay(Display *adisplay) { display = adisplay; }
static HardwareRegistry* GetHwRegistry()
{
if (!myself) myself = new HardwareRegistry;
ASSERT(myself); // If we don't have a pointer now, panic!
return myself;
}
};
Then you just have a Singleton Pattern to provide your HardwareRegistry, and register the devices as you create them during hardware initialization.
Of course, if you support different kinds of Keypads, Displays, etc, then you would implement those with a "interface baseclass", and the registry returns the KeypadBase type, for example.
For example, in an MFC program, I have my main application and a 'class'. What should I do if I want to update a control (say, a listbox) that is situated on my main application from that 'class'?
heres an example that worked for me
theApp.m_pMainWnd->GetDlgItem(IDC_BUTTON6)->SetWindowTextW(L"Run Auto Test");
Your class can be designed to trigger an event which your main application can listen for. Then, a listener/event handler/delegate can be called to handle the event and update the listbox. Typically, most event formats pass a reference of the sender, in this case your 'class', as well as an object containing event arguments. These arguments can be used to pass the list of items you want to add to your listbox.
If you have the handle to dialog object in your class, then you can use GetDlgItem(ResourceID) to get list control object.
The easiest approach is to expose the listview from your application form/window to the classes that use it. You can do this either by passing the listview object (or parent window) to the class constructor, or storing it in a static variable that is accessible by the class.
For better encapsulation, you can put a method in the application that the class can call, e.g. "AddItemToListBox()". This allows the application object to remain in control of how you access the listbox. Again you can do this as a static method, or pass the main program object's 'this' pointer into the class constructor.
i.e.
class CApplication
{
CListBox m_ListBox;
public:
static void CApplication::AddItemToListBox(CString itemText)
{
// Add the item as you wish here
}
}
class CMyClass
{
afx_msg void CMyClass::OnMouseDown(...)
{
CApplication::AddItemToListBox("This is a test");
}
}