C ++ WINAPI动态包装器类

Question

首先，我想说的是，对于那些要说“我为什么要重新发明轮子”的人，我这样做很有趣，而且是我目前正在从事的一个项目。

从下面的代码中可以看到，我试图动态创建一个窗口和一个按钮，但是我遇到的麻烦是在单击该按钮时向该按钮添加了功能。

我知道进入WM_COMMAND中的窗口过程并在那里进行操作非常简单，但这缺少了我要在此处完成的工作的全部要点，因此我可以简单地调用btn.add(params)到某个窗口，并通过说“ btn.click(function);”向该按钮添加某个功能，而无需在添加控件时进入窗口过程本身。

我该怎么做？

#include <Windows.h>
#include <vector>
#include <thread>

using namespace std;

WNDCLASSEX defWndClass = { 0 };

class WinForm
{
private:
    HWND WindowHandle;
    std::thread Thread;
    std::vector<std::tuple<std::string, std::size_t, HWND>> 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<std::tuple<std::string, std::size_t, HWND>>::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<std::tuple<std::string, std::size_t, HWND>>::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);
    }

}

Answer 1

单击按钮时，按钮的父窗口将通过WM_COMMAND接收BN_CLICKED通知。如果父窗口不处理该消息，它将最终转到DefWindowProc()并被忽略。因此，父窗口需要处理WM_COMMAND。当通知代码为BN_CLICKED时，只需在按钮列表中查找提供的按钮HWND，如果找到，则调用相应的函数（如果已分配）。

#include <Windows.h>
#include <vector>
#include <thread>
#include <algorithm>
#include <functional>

class WinForm
{
public:
    using ControlActionFunc = std::function<void(const std::string &)>;

    WinForm(std::string ClassName, std::string WindowName, bool Threaded = false, int Width = CW_USEDEFAULT, int Height = CW_USEDEFAULT);

    ~WinForm();

    bool AddButton(const std::string &ButtonName, POINT Location, int Width, int Height, ControlActionFunc OnClick);

private:
    HWND WindowHandle;
    std::thread Thread;

    using ControlInfo = std::tuple<std::string, std::size_t, HWND, ControlActionFunc>;
    using ControlInfoVector = std::vector<ControlInfo>;
    ControlInfoVector Controls;

    static LRESULT __stdcall StaticWindowProcedure(HWND window, UINT msg, WPARAM wp, LPARAM lp);

protected:
    virtual LRESULT WindowProcedure(UINT msg, WPARAM wp, LPARAM lp);
};

class MainAppWinForm : public WInForm
{
public:
    using WinForm::WinForm;

protected:
    LRESULT WindowProcedure(UINT msg, WPARAM wp, LPARAM lp) override;
};

WinForm::WinForm(std::string ClassName, std::string WindowName, bool Threaded, int Width, int Height)
    : WindowHandle(nullptr)
{
    HINSTANCE hInstance = GetModuleHandle(nullptr);
    WNDCLASSEX WndClass = {};

    bool isRegistered = GetClassInfoEx(hInstance, ClassName.c_str(), &WndClass);
    if ((!isRegistered) || (WndClass.lpfnWndProc != &WinForm::StaticWindowProcedure))
    {
        if (isRegistered)
            UnregisterClass(ClassName.c_str(), hInstance);

        WndClass.cbSize = sizeof(WNDCLASSEX);
        WndClass.style = CS_DBLCLKS;
        WndClass.lpfnWndProc = &WinForm::StaticWindowProcedure;
        WndClass.cbClsExtra = 0;
        WndClass.cbWndExtra = sizeof(WinForm*);
        WndClass.hInstance = hInstance;
        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))
            return;
    }

    if (Threaded)
    {
        // can't do that!
        return;
    }

    WindowHandle = CreateWindowEx(0, ClassName.c_str(), WindowName.c_str(), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, Width, Height, nullptr, nullptr, hInstance, this);
    if (!WindowHandle)
        return;

    ShowWindow(WindowHandle, SW_SHOWDEFAULT);

    // don't put message loop here!
}

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

LRESULT __stdcall WinForm::StaticWindowProcedure(HWND window, UINT msg, WPARAM wp, LPARAM lp)
{
    WinForm *This;
    if (msg == WM_NCCREATE)
    {
        This = static_cast<WinForm*>(reinterpret_cast<CREATESTRUCT*>(lp)->lpCreateParams);
        This->WindowHandle = window;
        SetWindowLongPtr(window, 0, reinterpret_cast<LONG_PTR>(This));
    }
    else
        This = reinterpret_cast<WinForm*>(GetWindowLongPtr(window, 0));

    if (This)
        return This->WindowProcedure(msg, wp, lp);

    return DefWindowProc(window, msg, wp, lp);
}

LRESULT WinForm::WindowProcedure(UINT msg, WPARAM wp, LPARAM lp)
{
    switch (msg)
    {
        /*
        case WM_PAINT:
            break;
        */

        case WM_COMMAND:
        {
            if (lp != 0)
            {
                if (HIWORD(wp) == BN_CLICKED)
                {
                    HWND ControlWindow = reinterpret_cast<HWND>(lp);

                    auto it = std::find_if(Controls.begin(), Controls.end(),
                        [](ControlInfo &info){ return (std::get<2>(info) == ControlWindow); }
                    );

                    if (it != Controls.end())
                    {
                        auto &tu = *it;
                        auto actionFunc = std::get<3>(tu);
                        if (actionFunc) actionFunc(std::get<0>(tu));
                        return 0;
                    }
                }
            }
            break;
        }

        case WM_CREATE:
            break;
    }

    return DefWindowProc(WindowHandle, msg, wp, lp);
}

bool WinForm::AddButton(const std::string &ButtonName, POINT Location, int Width, int Height, ControlActionFunc OnClick)
{
    auto it = std::find_if(Controls.begin(), Controls.end(),
        [&](ControlInfo &info){ return (std::get<0>(info).compare(ButtonName) == 0); }
    );

    if (it != Controls.end()) {
        return false;
    }

    std::size_t ID = 1;
    auto matchesID = [&](ControlInfo &info){ return (std::get<1>(tu) == ID); };
    while (std::find_if(Controls.begin(), Controls.end(), matchesID) != Controls.end()) {
        ++ID;
    }

    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);
    if (!ButtonHandle)
        return false;

    Controls.push_back(std::make_tuple(ButtonName, ID, ButtonHandle, std::move(OnClick)));
    return true;
}

LRESULT MainAppWinForm::WindowProcedure(UINT msg, WPARAM wp, LPARAM lp)
{
    if (msg == WM_DESTROY)
    {
        PostQuitMessage(0);
        return 0;
    }
    return WinForm::WindowProcedure(msg, wp, lp);
}

int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
    MainAppWinForm Form("Class", "Title", false);

    POINT pt = { 50, 50 };
    Form.AddButton("NewButton", pt, 80, 50,
        [](const std::string &ButtonName){ MessageBox(NULL, ButtonName.c_str(), "button clicked", MB_OK); }
    );

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

    return 0;
}

也可以看到

Class method for WndProc

Win32: More "object oriented" window message handling system

Best method for storing this pointer for use in WndProc