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Martin Hope
machine_1
Asked: 2024-08-10 16:11:01 +0800 CST
  • 6

我编写了一个代码来将窗口样式值解析为文本宏，但输出与样式值有很大不同；为什么以及如何修复它？

输出：

WS_CHILD | WS_VISIBLE | BS_GROUPBOX | BS_DEFPUSHBUTTON | BS_3STATE | BS_AUTOCHECKBOX | BS_AUTORADIOBUTTON | BS_OWNERDRAW | BS_TYPEMASK | SS_ETCHEDVERT | SS_OWNERDRAW | SS_TYPEMASK |

代码：

#include <windows.h>
#include <unordered_map>
#include <string>
#include <iostream>

class StyleMapSingleton {
private:
    std::unordered_map<DWORD, std::wstring> styleMap;
    StyleMapSingleton() {
        styleMap = {
            {WS_OVERLAPPED,         L"WS_OVERLAPPED"},
            {WS_POPUP,              L"WS_POPUP"},
            {WS_VISIBLE,            L"WS_VISIBLE"},
            {WS_CHILD,              L"WS_CHILD"},
            {WS_MINIMIZE,           L"WS_MINIMIZE"},
            {WS_DISABLED,           L"WS_DISABLED"},
            {WS_CLIPSIBLINGS,       L"WS_CLIPSIBLINGS"},
            {WS_CLIPCHILDREN,       L"WS_CLIPCHILDREN"},
            {WS_MAXIMIZE,           L"WS_MAXIMIZE"},
            {WS_BORDER,             L"WS_BORDER"},
            {WS_DLGFRAME,           L"WS_DLGFRAME"},
            {WS_VSCROLL,            L"WS_VSCROLL"},
            {WS_HSCROLL,            L"WS_HSCROLL"},
            {WS_SYSMENU,            L"WS_SYSMENU"},
            {WS_THICKFRAME,         L"WS_THICKFRAME"},
            {WS_GROUP,              L"WS_GROUP"},
            {WS_TABSTOP,            L"WS_TABSTOP"},
            {WS_MINIMIZEBOX,        L"WS_MINIMIZEBOX"},
            {WS_MAXIMIZEBOX,        L"WS_MAXIMIZEBOX"},

            {BS_PUSHBUTTON,         L"BS_PUSHBUTTON"},
            {BS_DEFPUSHBUTTON,      L"BS_DEFPUSHBUTTON"},
            {BS_RADIOBUTTON,        L"BS_RADIOBUTTON"},
            {BS_CHECKBOX,           L"BS_CHECKBOX"},
            {BS_3STATE,             L"BS_3STATE"},
            {BS_AUTO3STATE,         L"BS_AUTO3STATE"},
            {BS_AUTOCHECKBOX,       L"BS_AUTOCHECKBOX"},
            {BS_AUTORADIOBUTTON,    L"BS_AUTORADIOBUTTON"},
            {BS_GROUPBOX,           L"BS_GROUPBOX"},
            {BS_USERBUTTON,         L"BS_USERBUTTON"},
            {BS_BITMAP,             L"BS_BITMAP"},
            {BS_ICON,               L"BS_ICON"},
            {BS_FLAT,               L"BS_FLAT"},
            {BS_MULTILINE,          L"BS_MULTILINE"},
            {BS_OWNERDRAW,          L"BS_OWNERDRAW"},
            {BS_PUSHLIKE,           L"BS_PUSHLIKE"},
            {BS_LEFT,               L"BS_LEFT"},
            {BS_RIGHT,              L"BS_RIGHT"},
            {BS_CENTER,             L"BS_CENTER"},
            {BS_TOP,                L"BS_TOP"},
            {BS_BOTTOM,             L"BS_BOTTOM"},
            {BS_VCENTER,            L"BS_VCENTER"},
            {BS_RIGHTBUTTON,        L"BS_RIGHTBUTTON"},
            {BS_LEFTTEXT,           L"BS_LEFTTEXT"},
            {BS_TEXT,               L"BS_TEXT"},
            {BS_NOTIFY,             L"BS_NOTIFY"},
            {BS_TYPEMASK,           L"BS_TYPEMASK"},

            {CBS_AUTOHSCROLL,       L"CBS_AUTOHSCROLL"},
            {CBS_DISABLENOSCROLL,   L"CBS_DISABLENOSCROLL"},
            {CBS_DROPDOWN,          L"CBS_DROPDOWN"},
            {CBS_DROPDOWNLIST,      L"CBS_DROPDOWNLIST"},
            {CBS_HASSTRINGS,        L"CBS_HASSTRINGS"},
            {CBS_LOWERCASE,         L"CBS_LOWERCASE"},
            {CBS_NOINTEGRALHEIGHT,  L"CBS_NOINTEGRALHEIGHT"},
            {CBS_OEMCONVERT,        L"CBS_OEMCONVERT"},
            {CBS_OWNERDRAWFIXED,    L"CBS_OWNERDRAWFIXED"},
            {CBS_OWNERDRAWVARIABLE, L"CBS_OWNERDRAWVARIABLE"},
            {CBS_SIMPLE,            L"CBS_SIMPLE"},
            {CBS_SORT,              L"CBS_SORT"},

            {ES_AUTOHSCROLL,        L"ES_AUTOHSCROLL"},
            {ES_AUTOVSCROLL,        L"ES_AUTOVSCROLL"},
            {ES_LEFT,               L"ES_LEFT"},
            {ES_CENTER,             L"ES_CENTER"},
            {ES_RIGHT,              L"ES_RIGHT"},
            {ES_LOWERCASE,          L"ES_LOWERCASE"},
            {ES_UPPERCASE,          L"ES_UPPERCASE"},
            {ES_OEMCONVERT,         L"ES_OEMCONVERT"},
            {ES_NUMBER,             L"ES_NUMBER"},
            {ES_PASSWORD,           L"ES_PASSWORD"},
            {ES_MULTILINE,          L"ES_MULTILINE"},
            {ES_WANTRETURN,         L"ES_WANTRETURN"},
            {ES_NOHIDESEL,          L"ES_NOHIDESEL"},
            {ES_READONLY,           L"ES_READONLY"},

            {SS_BLACKFRAME,         L"SS_BLACKFRAME"},
            {SS_GRAYFRAME,          L"SS_GRAYFRAME"},
            {SS_WHITEFRAME,         L"SS_WHITEFRAME"},
            {SS_ETCHEDFRAME,        L"SS_ETCHEDFRAME"},
            {SS_ETCHEDHORZ,         L"SS_ETCHEDHORZ"},
            {SS_ETCHEDVERT,         L"SS_ETCHEDVERT"},
            {SS_BLACKRECT,          L"SS_BLACKRECT"},
            {SS_WHITERECT,          L"SS_WHITERECT"},
            {SS_GRAYRECT,           L"SS_GRAYRECT"},
            {SS_CENTERIMAGE,        L"SS_CENTERIMAGE"},
            {SS_REALSIZEIMAGE,      L"SS_REALSIZEIMAGE"},
            {SS_REALSIZECONTROL,    L"SS_REALSIZECONTROL"},
            {SS_LEFT,               L"SS_LEFT"},
            {SS_CENTER,             L"SS_CENTER"},
            {SS_RIGHT,              L"SS_RIGHT"},
            {SS_RIGHTJUST,          L"SS_RIGHTJUST"},
            {SS_EDITCONTROL,        L"SS_EDITCONTROL"},
            {SS_SIMPLE,             L"SS_SIMPLE"},
            {SS_SUNKEN,             L"SS_SUNKEN"},
            {SS_ENDELLIPSIS,        L"SS_ENDELLIPSIS"},
            {SS_PATHELLIPSIS,       L"SS_PATHELLIPSIS"},
            {SS_WORDELLIPSIS,       L"SS_WORDELLIPSIS"},
            {SS_ICON,               L"SS_ICON"},
            {SS_BITMAP,             L"SS_BITMAP"},
            {SS_ENHMETAFILE,        L"SS_ENHMETAFILE"},
            {SS_LEFTNOWORDWRAP,     L"SS_LEFTNOWORDWRAP"},
            {SS_NOPREFIX,           L"SS_NOPREFIX"},
            {SS_NOTIFY,             L"SS_NOTIFY"},
            {SS_OWNERDRAW,          L"SS_OWNERDRAW"},
            {SS_TYPEMASK,           L"SS_TYPEMASK"},
        };
    }
    StyleMapSingleton(const StyleMapSingleton&) = delete;
    void operator=(const StyleMapSingleton&) = delete;
public:
    static StyleMapSingleton& getInstance() {
        static StyleMapSingleton instance;
        return instance;
    }
    const std::unordered_map<DWORD, std::wstring>& getStyleMap() const {
        return styleMap;
    }
};

void resolveWindowStyle(DWORD style, const std::unordered_map<DWORD, std::wstring>& styleMap) {
    for (const auto& entry : styleMap) {
        if (style & entry.first) {
            std::wcout << entry.second << L" | ";
        }
    }
    std::wcout << std::endl;
}

int main() {
    const auto& styleMapInst = StyleMapSingleton::getInstance();
    DWORD style = WS_CHILD | WS_VISIBLE | ES_CENTER;
    resolveWindowStyle(style, styleMapInst.getStyleMap());
    return 0;
}
c++
Martin Hope
machine_1
Asked: 2024-03-06 21:32:20 +0800 CST
  • -1

C++ 允许使用virtual关键字定义成员函数的默认行为，但是如果我想扩展成员函数以执行附加功能怎么办？例如，我有以下代码：

virtual void OnSize(HWND hWnd, LPARAM lParam) {
    cxClient = LOWORD(lParam);
    cyClient = HIWORD(lParam);

    rect = { 0, 0, cxClient, cyClient };
}

cxClient、cyClient、 和rect是在接收消息时更新的成员变量WM_SIZE。如果我想更新继承类中的滚动条，我必须重写该函数以添加此功能，但随后我需要重复用于更新成员变量的代码：

void OnSize(HWND hWnd, LPARAM lParam) override {
    cxClient = LOWORD(lParam);
    cyClient = HIWORD(lParam);

    rect = { 0, 0, cxClient, cyClient };

    vScrollBar->setInfo(cyClient); // new functionality
}

为什么C++不提供extend关键字来允许扩展虚函数的默认行为，即保留默认行为并合并附加功能。例如：

void OnSize(HWND hWnd, LPARAM lParam) extend {
    vScrollBar->setInfo(cyClient); // new functionality
}

即将发布的 C++ 修订版是否考虑了这一点？

c++