windows api学习笔记-简单的记事本

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#include <windows.h>

#include "resource.h"

#include <string>

 

LRESULT CALLBACK MainWndProc(HWND,UINT,WPARAM,LPARAM);//窗口函数的函数原型

 

int APIENTRY WinMain(                               //APIENTRY是__stdcall的宏定义

                     HINSTANCE hInstance,           //本模块的实例句柄

                     HINSTANCE hPrevInstance,       //Win16留下的废物

                     LPSTR lpCmdLine,               //命令行参数

                     int nCmdShow                   //主窗口初始化时的现实形式

                     )

{

    char szClassName[] = "MainClass";

    WNDCLASSEX wndclass;   //用来描述主窗口的结构

    wndclass.cbSize = sizeof(wndclass);  //结构的大小

    wndclass.style = CS_HREDRAW|CS_VREDRAW; //如果窗口大小，横向改变和竖向改变都会重画窗口

    wndclass.lpfnWndProc = MainWndProc;//窗口函数指针

    wndclass.cbClsExtra = 0;//没有额外的类内存

    wndclass.cbWndExtra = 0;//没有额外的窗口内存

    wndclass.hInstance = hInstance;//实例句柄

    wndclass.hIcon = ::LoadIcon(NULL,IDI_APPLICATION);//使用预定义图标

    wndclass.hCursor = ::LoadCursor(NULL,IDC_ARROW);//使用预定义光标

    wndclass.hbrBackground = (HBRUSH)::GetStockObject(WHITE_BRUSH);//使用白色背景画刷

    wndclass.lpszMenuName = (LPSTR)IDR_MENU1;//指定菜单,菜单在头文件中已经定义了

    wndclass.lpszClassName = szClassName;//窗口类的名称

    wndclass.hIconSm = NULL;//没有类的小图标

 

    ::RegisterClassEx(&wndclass);//注册这个窗口类

 

    HWND hwnd = ::CreateWindowEx(

        0,//扩展样式

        szClassName,//类名

        "My First Window",//窗口名。标题

        WS_OVERLAPPEDWINDOW,//窗口风格

        CW_USEDEFAULT,//初始X坐标

        CW_USEDEFAULT,//初始Y坐标

        CW_USEDEFAULT,//宽度

        CW_USEDEFAULT,//高度

        NULL,//父窗口句柄

        NULL,//菜单句柄

        hInstance,//实例句柄

        NULL//用户数据

        );

    if(hwnd == NULL)

    {

        ::MessageBox(NULL,"创建窗口出错","系统提示",MB_OK);

    }

    ::ShowWindow(hwnd,nCmdShow);//显示窗口

    ::UpdateWindow(hwnd);//刷新窗口

    MSG msg;

    while(::GetMessage(&msg,NULL,0,0))

    {

        ::TranslateMessage(&msg);//转换为键盘消息

        ::DispatchMessage(&msg);//将消息发送到相应的窗口函数

    }

    return msg.wParam;//当GetMessage返回FALSE时程序结束

}

 

LRESULT CALLBACK MainWndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam)

{

    static std::string str;

    switch(message)

    {

        case WM_CREATE:

            {

                ::SetWindowText(hwnd,"打字程序");

                return 0;

            }

        case WM_CHAR:

            {

                str = str+char(wParam);

                ::InvalidateRect(hwnd,NULL,0);//使整个客户区无效,迫使系统再次发送WM_PAINT消息

                return 0;

            }

        case WM_PAINT:

            {

                HDC hdc;

                PAINTSTRUCT ps;

                hdc = ::BeginPaint(hwnd,&ps);//使无效的客户区变的有效，并取得设备环境句柄

                ::TextOut(hdc,0,0,str.c_str(),str.length());//输出文本

                ::EndPaint(hwnd,&ps);

                return 0;

            }

        case WM_DESTROY:

            {

                ::PostQuitMessage(0);//向消息队列投递一个WM_QUIT消息，促使GET MESSAGE函数返回0，结束消息循环

                return 0;

            }

        case WM_COMMAND:

            {

                switch(LOWORD(wParam))

                {

                    case ID_FILE_EXIT:

                        ::SendMessage(hwnd,WM_CLOSE,0,0);

                        break;

                }

                return 0;

            }

    }

    return ::DefWindowProc(hwnd,message,wParam,lParam);

}

resource.h的代码为

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//{{NO_DEPENDENCIES}}

// Microsoft Visual C++ generated include file.

// Used by a.rc

//

#define IDR_MENU1                       101

#define ID_FILE_EXIT                    40001

 

// Next default values for new objects

//

#ifdef APSTUDIO_INVOKED

#ifndef APSTUDIO_READONLY_SYMBOLS

#define _APS_NEXT_RESOURCE_VALUE        102

#define _APS_NEXT_COMMAND_VALUE         40002

#define _APS_NEXT_CONTROL_VALUE         1001

#define _APS_NEXT_SYMED_VALUE           101

#endif

#endif