第三章、窗口与消息

#include <Windows.h>
#include <mmsystem.h>
#pragma comment(lib, "WINMM.LIB")
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
HWND hwnd;
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("HelloWin");
    
    MSG msg;
    WNDCLASS wndclass;

    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL,IDI_APPLICATION);                //加载图标，以供程序使用
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);                    //加载鼠标光标，以供程序使用
    wndclass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);    //获取一个图形对象，本例中用来对窗口的背景进行重绘的画刷。
    wndclass.lpszClassName = szAppName;            
    wndclass.lpszMenuName = NULL;

    if(!RegisterClass(&wndclass))                                    //为应用程序的窗口注册一个窗口类
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),szAppName, MB_ICONERROR);//显示消息框
        return 0;
    }

    hwnd = CreateWindow(szAppName,
                        TEXT("The Hello Program"),
                        WS_OVERLAPPEDWINDOW,
                        CW_USEDEFAULT,
                        CW_USEDEFAULT,
                        CW_USEDEFAULT,
                        CW_USEDEFAULT,
                        NULL,
                        NULL,
                        hInstance,
                        NULL);                                        //基于窗口类创建一个窗口

    ShowWindow(hwnd, iCmdShow);                                        //在屏幕中显示窗口
    UpdateWindow(hwnd);                                                //指示窗口对其自身进行重绘

    while(GetMessage(&msg,NULL,0,0))                                //从消息队列获取消息
    {
        TranslateMessage(&msg);                                        //翻译一些键盘消息
        DispatchMessage(&msg);                                        //将消息发送给窗口过程
    }

    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:
        PlaySound(TEXT("hellowin.wav"),NULL,SND_FILENAME | SND_ASYNC);//播放声音文件
        return 0;
    case WM_PAINT:
        hdc = BeginPaint(hwnd,&ps);                                    //标明窗口绘制开始
        GetClientRect(hwnd,&rect);                                    //获取窗口客户区的尺寸
        DrawText(hdc, TEXT("Hello, Windows 98!"), -1, &rect, DT_SINGLELINE | DT_CENTER | DT_VCENTER);//显示一个文本字符串
        EndPaint(hwnd,&ps);                                            //结束窗口绘制
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);                                            //将“退出”消息插入消息队列
        return 0;
    }
    return DefWindowProc(hwnd,message,wParam,lParam);                //执行默认的消息处理
}