一.创建一个windows程序步骤
1.创建一个windows类
2.创建一个事件处理程序
3.注册windows类
4.用之前创建的windows类创建一个窗口
5.创建一个主事件循环
二.存储windows类信息的数据结构：
typedef struct _WNDCLASSEX
{
UINT cbSize; // size of this structure
UINT style; // style flags
WNDPROC lpfnWndProc; // function pointer to handler
int cbClsExtra; // extra class info
int cbWndExtra; // extra window info
HANDLE hInstance; // the instance of the application
HICON hIcon; // the main icon
HCURSOR hCursor; // the cursor for the window
HBRUSH hbrBackground; // the background brush to paint the window
LPCTSTR lpszMenuName; // the name of the menu to attach
LPCTSTR lpszClassName; // the name of the class itself
HICON hIconSm; // the handle of the small icon
} WNDCLASSEX
cbSize=sizeof(WNDCLASSEX);
style值：
winclass.style = CS_VREDRAW | CS_HREDRAW | CS_OWNDC | CS_DBLCLICKS;
CS_HREDRAW
Redraws the entire window if a movement or size adjustment changes the width of the window.
CS_VREDRAW
Redraws the entire window if a movement or size adjustment changes the height of the window.
CS_OWNDC
Allocates a unique device context for each window in the class (more on this later in the chapter).
CS_DBLCLKS
Sends a double-click message to the window procedure when the user double-clicks the mouse while the cursor is in a window belonging to the class.
CS_PARENTDC
Sets the clipping region of the child window to that of the parent window so that the child can draw on the parent.
CS_SAVEBITS
Saves the client image in a window so you don't have to redraw it every time the window is obscured, moved, etc. However, this takes up more memory and is slower that doing it yourself.
CS_NOCLOSE
Disables the Close command on the system menu.
Note: The most commonly used flags are highlighted.
lpfnWndProc窗口事件处理函数指针：
完整定义：
WNDCLASSEX winclass; // this will hold the class we create
// first fill in the window class structure
inclass.cbSize = sizeof(WNDCLASSEX);
winclass.style = CS_DBLCLKS | CS_OWNDC | CS_HREDRAW | CS_VREDRAW;
winclass.lpfnWndProc = WindowProc;
winclass.cbClsExtra = 0;
winclass.cbWndExtra = 0;
winclass.hInstance = hinstance;
winclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
winclass.hCursor = LoadCursor(NULL, IDC_ARROW);
winclass.hbrBackground = GetStockObject(BLACK_BRUSH);
winclass.lpszMenuName = NULL;
winclass.lpszClassName = "WINCLASS1";
winclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
三.注册windows类
RegisterClassEx(&winclass);
四.创建窗口
HWND CreateWindowEx(
DWORD dwExStyle, // extended window style
LPCTSTR lpClassName, // pointer to registered class name
LPCTSTR lpWindowName, // pointer to window name
DWORD dwStyle, // window style
int x, // horizontal position of window
int y, // vertical position of window
int nWidth, // window width
int nHeight, // window height
HWND hWndParent, // handle to parent or owner window
HMENU hMenu, // handle to menu, or child-window identifier
HINSTANCE hInstance, // handle to application instance
LPVOID lpParam); // pointer to window-creation data
HWND hwnd; // window handle // create the window, bail if problem
if (!(hwnd = CreateWindowEx(NULL, // extended style
"WINCLASS1", // class
"Your Basic Window", // title
WS_OVERLAPPEDWINDOW | WS_VISIBLE,
0,0, // initial x,y
400,400, // initial width, height
NULL, // handle to parent
NULL, // handle to menu
hinstance, // instance of this application
NULL))) // extra creation parms
return(0);
Once the window has been created, it may or may not be visible. However, in this case, we added the style flag WS_VISIBLE, which does this automatically. If this flag isn't added, use the following function call to manually display the window:
// this shows the window
ShowWindow(hwnd, ncmdshow);
五.事件处理程序
WinProc原型：
LRESULT CALLBACK WindowProc(
HWND hwnd, // window handle of sender
UINT msg, // the message id
WPARAM wparam, // further defines message
LPARAM lparam); // further defines message
实例：
LRESULT CALLBACK WindowProc(HWND hwnd,
UINT msg,
WPARAM wparam,
LPARAM lparam)
{
// this is the main message handler of the system
PAINTSTRUCT ps; // used in WM_PAINT
HDC hdc; // handle to a device context // what is the message
switch(msg)
{
case WM_CREATE:
{
// do initialization stuff here // return success
return(0);
} break; case WM_COMMAND:
{
switch(LOWORD(wparam))
{
// handle the FILE menu
case MENU_FILE_ID_OPEN:
{
// do work here
} break;
case MENU_FILE_ID_CLOSE:
{
// do work here
} break;
case MENU_FILE_ID_SAVE:
{
// do work here
} break;
case MENU_FILE_ID_EXIT:
{
// do work here
} break; // handle the HELP menu
case MENU_HELP_ABOUT:
{
// do work here
} break;
default: break; } // end switch wparam } break; // end WM_COMMAND case WM_PAINT:
{
// simply validate the window
hdc = BeginPaint(hwnd,&ps);
// you would do all your painting here
EndPaint(hwnd,&ps);
// return success
return(0);
} break; case WM_DESTROY:
{
// kill the application, this sends a WM_QUIT message
PostQuitMessage(0); // return success
return(0);
} break; default:break; } // end switch // process any messages that we didn't take care of
return (DefWindowProc(hwnd, msg, wparam, lparam)); } // end WinProc
六.主事件循环
// enter main event loop
while(GetMessage(&msg,NULL,0,0))
{
// translate any accelerator keys
TranslateMessage(&msg);
// send the message to the window proc
DispatchMessage(&msg);
} // end while
事件循环处理消息机制流程图：
