C++ WINAPI Dynamic Wrapper Class

Question

First off, I want to say, for anyone who is going to say "why am I reinventing the wheel", I am doing this for fun, and for a project of mine I'm currently working on.

As you can see from the code below, I am trying to dynamically create a window and a button, but something I'm having trouble with is adding a function to that button when it's clicked.

I know it would be really simple to go into the window procedure in WM_COMMAND and do so there, but that's missing the whole point of what I'm trying to accomplish here, have it so I can simple call btn.add(params) to a certain window, and add a certain function to that button by calling say btn.click(function); without having to go into the window procedure itself when adding the controls.

How would I accomplish this?

#include 
#include 
#include 

using namespace std;

WNDCLASSEX defWndClass = { 0 };

class WinForm
{
private:
    HWND WindowHandle;
    std::thread Thread;
    std::vector> ControlHandles;

public:
    ~WinForm();
    WinForm(std::string ClassName, std::string WindowName, bool Threaded = false, int Width = CW_USEDEFAULT,
        int Height = CW_USEDEFAULT, WNDPROC WindowProcedure = nullptr, WNDCLASSEX WndClass = defWndClass);
    bool AddButton(std::string ButtonName, POINT Location, int Width, int Height);
};

WinForm::~WinForm()
{
    if (Thread.joinable())
    {
        Thread.join();
    }
}

WinForm::WinForm(std::string ClassName, std::string WindowName, bool Threaded, int Width, int Height, WNDPROC WindowProcedure, WNDCLASSEX WndClass)
    :WindowHandle(nullptr)
{
    if (WindowProcedure == nullptr)
    {
        WindowProcedure = [](HWND window, UINT msg, WPARAM wp, LPARAM lp)->LRESULT __stdcall
        {
            switch (msg)
            {
                /*
                case WM_PAINT:
                    break;
                    */

            case WM_DESTROY:
                PostQuitMessage(0);
                return 0;

            case WM_CREATE:
                break;

            default:
                return DefWindowProc(window, msg, wp, lp);
            }
            return 0;
        };
    }

    if (WndClass.cbSize == 0)
    {
        WndClass.cbSize = sizeof(WNDCLASSEX);
        WndClass.style = CS_DBLCLKS;
        WndClass.lpfnWndProc = WindowProcedure;
        WndClass.cbClsExtra = 0;
        WndClass.cbWndExtra = 0;
        WndClass.hInstance = GetModuleHandle(nullptr);
        WndClass.hIcon = LoadIcon(nullptr, IDI_APPLICATION);
        WndClass.hCursor = LoadCursor(nullptr, IDC_ARROW);
        WndClass.hbrBackground = HBRUSH(COLOR_WINDOW + 1);
        WndClass.lpszMenuName = nullptr;
        WndClass.lpszClassName = ClassName.c_str();
        WndClass.hIconSm = LoadIcon(nullptr, IDI_APPLICATION);
    }

    if (RegisterClassEx(&WndClass))
    {
        if (Threaded)
        {
            // can't do that!
        }
        else
        {
            WindowHandle = CreateWindowEx(0, ClassName.c_str(), WindowName.c_str(), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, Width, Height, nullptr, nullptr, GetModuleHandle(nullptr), nullptr);
            if (WindowHandle)
            {
                ShowWindow(WindowHandle, SW_SHOWDEFAULT);

                // don't put message loop here!
            }
        }
    }
}

bool WinForm::AddButton(std::string ButtonName, POINT Location, int Width, int Height)
{
    for (std::vector>::iterator it = ControlHandles.begin(); it != ControlHandles.end(); ++it)
    {
        auto& tu = *it;
        auto& str = std::get<0>(tu);
        if (ButtonName.compare(str) == 0) {
            return false;
        }
    }

    std::size_t ID = 1;
    for (std::vector>::iterator it = ControlHandles.begin(); it != ControlHandles.end(); ++it, ++ID)
    {
        if (std::get<1>(*it) != ID)
        {
            break;
        }
    }

    HWND ButtonHandle = CreateWindowEx(
        0, "button", ButtonName.c_str(), WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, Location.x, Location.y, Width, Height,
        WindowHandle, (HMENU)ID, (HINSTANCE)GetWindowLong(WindowHandle, GWL_HINSTANCE), nullptr);
    ShowWindow(ButtonHandle, SW_SHOW);
    ControlHandles.push_back(std::make_tuple(ButtonName, ID, ButtonHandle));

    //SendMessage(WindowHandle, WM_CREATE, 0, 0);
    return true;
}

int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
    WinForm Form("Class", "Title", false);
    POINT pt = { 50, 50 };
    Form.AddButton("NewButton", pt, 80, 50);

    MSG msg = { nullptr };
    while (GetMessage(&msg, nullptr, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

}

C++ WINAPI Dynamic Wrapper Class

Answers (1)

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