Visual C++面向对象与可视化编程

输出

#include<windows.h>

//窗口处理函数WndProc()的声明
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

//主函数，程序的入口，相当于之前的main()函数
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
				   PSTR szCmdLine, int iCmdShow)
{
	static char szAppName[] = "HelloWin";
	HWND hwnd;
	MSG msg;
	WNDCLASS wndclass;//WNDCLASSEX也行，会多几个分量，配合RegisterClassEX使用
	
	//设置WNDCLASS结构体，为下一步调用RegisterClass()函数做准备
	wndclass.style = CS_HREDRAW | CS_VREDRAW;//支持重绘，不能为0
	wndclass.lpfnWndProc = WndProc;//主函数与窗口处理函数绑定
	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(WHITE_BRUSH);
	wndclass.lpszMenuName = NULL;
	wndclass.lpszClassName = szAppName;
	
	//注册
	if (!RegisterClass(&wndclass))
	{
		MessageBox(NULL, "This program requires Windows NT!",
			szAppName, MB_ICONERROR);
		return 0;
	}

	//调用CreateWindow()函数创建窗体
	hwnd = CreateWindow (szAppName,                  // window class name
		"The Windows 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

	//显示和更新窗口
	ShowWindow(hwnd, iCmdShow);
	UpdateWindow(hwnd);
	
	//消息循环，不停接收消息直至收到WM_QUIT消息后，跳出循环，程序结束
	while (GetMessage(&msg, NULL, 0, 0))//如果函数取得WM_QUIT之外的其他消息，返回非零值。如果函数取得WM_QUIT消息，返回值是零
	{
		TranslateMessage(&msg);//翻译消息，将按键消息转换为字符消息
		DispatchMessage(&msg);//以此消息为参数转发给相应的窗口消息处理程序
	}
	return msg.wParam;
}

//窗口处理函数，函数格式固定，函数名无所谓
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	//Code here!

	HDC         hdc ;
	PAINTSTRUCT ps ;
	RECT        rect ;
	
	//分支结构，处理各种消息
	switch (message)
	{
	//绘图，很多情况下会被调用
	case WM_PAINT:
		hdc = BeginPaint (hwnd, &ps) ;
		
		GetClientRect (hwnd, &rect) ;
		
		DrawText (hdc, TEXT ("Hello, Windows!"), -1, &rect, DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;
		EndPaint (hwnd, &ps) ;
		return 0 ;
	
	//用户点击关闭窗体按钮时触发
	case WM_DESTROY:
		PostQuitMessage (0) ;//发出WM_QUIT消息，终止消息循环
		return 0 ;
	}
	
	//缺省采用系统消息默认处理函数
	return DefWindowProc (hwnd, message, wParam, lParam) ;	
}

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