一个窗口程序
#include "stdafx.h"
#include <windows.h>
LONG WINAPI WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpszCmdLine,
int nCmdShow)
{
WNDCLASS wc;
HWND hwnd;
MSG msg;
BOOL bRet;
/*
*初始化窗口
*/
wc.style = 0;
wc.lpfnWndProc = (WNDPROC)WndProc;//窗口程序地址
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;//实例句柄
wc.hIcon = LoadIcon(NULL, IDI_WINLOGO);//图标句柄
wc.hCursor = LoadCursor(NULL, IDC_ARROW);//光标句柄
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);//背景色
wc.lpszMenuName = NULL;
wc.lpszClassName = L"MyWdnClass";//加L把字符串转换成unicode字符串，
//这种字符串一个字符占两个字节 而一般ASCII字符是占一个字节
RegisterClass(&wc);//注册窗口
/*
*创建窗口
*/
hwnd = CreateWindow(L"MyWndClass",
L"SDK APPlication",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,//水平位置
CW_USEDEFAULT,//垂直位置
CW_USEDEFAULT,//初始化宽度
CW_USEDEFAULT,//初始化高度
HWND_DESKTOP,//父窗口句柄
NULL,//菜单句柄
hInstance,//程序实例句柄
NULL//窗口创建日期
);
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while ((bRet = GetMessage(&msg, NULL, 0, 0)) != 0)
{
if (bRet == 0 || bRet == -1)
{
return -1;
}
else
{
TranslateMessage(&msg);//将虚拟键消息转换为字符消息
DispatchMessage(&msg);//将消息发送给窗口
}
}
return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd,
UINT message,//消息ID
WPARAM wParam,
LPARAM lParam)
{
PAINTSTRUCT ps;
HDC hdc;
switch (message)
{
case WM_PAINT:
hdc = BeginPaint(hwnd, &ps);//获得设备环境句柄,准备指定的窗口来重绘并
//将绘画相关的信息放到一个PAINTSTRUCT结构中
Ellipse(hdc, 0, 0, 200, 100 );//绘制椭圆
EndPaint(hwnd, &ps);
return 0;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd, message, wParam, lParam);
}
编译时出现错误信息：”无法解析的外部符号 _main，该符号在函数 ___tmainCRTStartup 中被引用“
然后在网上查找到了原因：这个问题表明你新建的是一个main类型函数（控制台程序），而你的程序中有窗口程序，显然是个win32函数，解决方法：
项目－属性－链接器－系统－子系统－把控制台该为windows
但还是出错，原因如下：
实在感觉不再爱了。。。。。。
WNDCLASS structure
| LpfnWndProc | window proc, must be AfxWndProc |
| CbClsExtra | not used (should be zero) |
| CbWndExtra | not used (should be zero) |
| HInstance | automatically filled with AfxGetInstanceHandle |
| HIcon | icon for frame windows, see below |
| HCursor | cursor for when mouse is over window, see below |
| HbrBackground | background color, see below |
| LpszMenuName | not used (should be NULL) |
| LpszClassName | class name, see below |
The MSG structure
typedef struct tagMSG { // msg
HWND hwnd;
UINT message;
WPARAM wParam;
LPARAM lParam;
DWORD time;
POINT pt;
} MSG;
The MSG structure contains message information from a thread’s message queue.
Members
hwnd
Identifies the window whose window procedure receives the message.
message
Specifies the message number.
wParam
Specifies additional information about the message. The exact meaning depends on the value of the message member.
lParam
Specifies additional information about the message. The exact meaning depends on the value of the message member.
time
Specifies the time at which the message was posted.
pt
Specifies the cursor position, in screen coordinates, when the message was posted.
