Window Program 之 窗口與消息

這裏先放一個簡單的hello world 小程序做爲sample， 參考自 《windows程序設計(第五版)》

WinMain()爲程序入口

主函數的執行流程：

初始化窗口類 -> 註冊窗口類(RegisterClass) -> 建立窗口(CreateWindow) ->顯示窗口(ShowWindow) -> 刷新窗口(UpdateWindow) ->消息隊列循環(獲取消息(GetMessage) -> 分發消息(dispatchMessage))

窗口進程WndProc，做用是根據收到的各類消息執行對應邏輯

如，

執行 CreateWindow 時， 會收到 WM_CREATE

執行 窗口重刷（頁面放大縮小，ShowWindow，UpdateWindow） 時， 會收到 WM_PAINT

關閉窗體時，收到WM_DESTORY

 

消息分無兩種:

1. 隊列消息：加入消息隊列，等待消息隊列分發消息通知WndProc，如button相關的操做

2. 非隊列消息：直接通知WndProc，如 ShowWindow，UpdateWindow

#include "stdafx.h"
#include <windows.h>

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT ("123") ;
    HWND    hwnd ;
    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) ;
      wndclass.hCursor      = LoadCursor (NULL, IDC_ARROW) ;
     wndclass.hbrBackground    = (HBRUSH) GetStockObject (BLACK_BRUSH) ;
    wndclass.lpszMenuName    = NULL ;
    wndclass.lpszClassName    = szAppName ;

    if (!RegisterClass (&wndclass))
     {
        MessageBox (    NULL, TEXT ("This program requires Windows NT!"), 
                          szAppName, MB_ICONERROR) ;
        return 0 ;
     }
    hwnd = CreateWindow( szAppName,    // window class name
            TEXT ("The Hello Program"),    // window caption
            WS_OVERLAPPEDWINDOW,    // window style
            CW_USEDEFAULT,    // initial x position
            CW_USEDEFAULT,    // initial y position
            CW_USEDEFAULT,    // initial x size
            CW_USEDEFAULT,    // initial y size
            NULL,            // parent window handle
            NULL,            // window menu handle
            hInstance,        // program instance handle
            NULL) ;         // creation parameters
     
    ShowWindow (hwnd, iCmdShow) ;
    UpdateWindow (hwnd) ;
     
    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:
        return 0 ;

    case     WM_PAINT:
        hdc = BeginPaint (hwnd, &ps) ;
          
        GetClientRect (hwnd, &rect) ;
          
        DrawText (hdc, TEXT ("Hello, Windows 98!"), -1, &rect,
            DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;
              EndPaint (hwnd, &ps) ;
            return 0 ;
          
    case    WM_DESTROY:
        PostQuitMessage (0) ;
        return 0 ;
     }
   return DefWindowProc (hwnd, message, wParam, lParam) ;
}