Win32API實現的第一個窗口程序

代碼

流程
在Windows上，一個窗口程序是由消息驅動的，所以創建一個窗口程序有如下幾個步驟：

• 註冊窗口類，包括WNDCLASS結構體的賦值以及RegisterClass註冊窗口類
• 使用CreateWindow創建窗口以及ShowWindow和UpdateWindow更新顯示窗口
• 使用GetMessage和DispatchMessage建立消息循環
• 完成處理消息的WndProc回調函數

#include <windows.h>

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR lpCmdLine, int nCmdShow)
{
    char *lpClassName = "FirstWin", *lpWindowName = "Title";
    HWND hwnd;
    MSG msg;
    WNDCLASSEX wndclass;

    wndclass.cbSize = sizeof(wndclass);       // 指定該結構體的大小
    wndclass.style = CS_HREDRAW | CS_VREDRAW; // 寬度高度變化時重繪
    wndclass.lpfnWndProc = WndProc;           // 窗口回調函數
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);    // NULL表示系統圖標，默認圖標
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);      // 默認光標
    wndclass.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1); // 使用畫刷填充背景色，還可以(HBRUSH)GetStockObject(BLACK_BRUSH)
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = lpClassName;
    wndclass.hIconSm = NULL;

    if (!RegisterClassEx(&wndclass))
    {
        MessageBox(NULL, "Register Failed", "Tips", MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(lpClassName,
                        lpWindowName,
                        WS_OVERLAPPEDWINDOW, //style
                        CW_USEDEFAULT,       // x
                        CW_USEDEFAULT,       // y
                        600,                 // width
                        400,                 // height
                        NULL,                // hWndParent
                        NULL,                // hMenu
                        hInstance,           // hInstance
                        NULL);
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd); // 發送 WM_PAINT，保證窗口一定可以刷新顯示

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    RECT rect;

    switch (message)
    {
    case WM_CREATE:
        MessageBox(NULL, "Create Windows Success", "Tips", MB_OK);
        break;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        GetClientRect(hwnd, &rect);
        DrawText(hdc, "HelloWorld", -1, &rect, DT_SINGLELINE | DT_CENTER | DT_VCENTER);
        EndPaint(hwnd, &ps);
        break;
    case WM_CLOSE:
        DestroyWindow(hwnd);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}

使用gcc -m32 -mwindows win1.c -o win1.exe編譯

運行結果

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