Windows程序代码重构

Posted 2020-10-01 HANCAO

代码重构：在程序功能实现之后，对代码进行一定规模的整理，使之符合“高内聚、低耦合”的软件设计原则，便于维护和使用。

　　①用函数封装消息处理代码——对Windows程序窗口函数中的每一个case程序段进行封装以形成一个消息处理函数，而在case中调用这个函数。

　　②利用数组或链表实现消息映射表进一步实现代码的隔离——因为窗口函数switch…case结构实质上实现的就是一个根据消息标识来查找消息处理代码的功能，故可以用消息映射表和一段查表程序来替代它，表中的每一项可以使用一个函数指针来指向消息处理函数。

 固定的程序框架代码可以想办法用Windows程序开发工具自动生成，以减少程序员的工作量。

观察者模式（衍生于Windows消息发送者和消息处理者分开的做法）——java利用观察者模式实现了事件监听器模型、C#演化出了独特的事件委托模型。

  1 #include<windows.h>
  2 
  3 HINSTANCE hInst;
  4 HWND      hWnd;
  5 MSG          msg;
  6 char      lpszClassName[] = "窗口";
  7 char      *ShowText;
  8 
  9 ATOM      MyRegisterClass(HINSTANCE hInstance);
 10 BOOL      Create(HINSTANCE,int);
 11 int          Run();
 12 
 13 LRESULT   CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 14 void      OnLButtonDown(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
 15 void      OnPaint(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam);
 16 void      OnDestroy(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam);
 17 
 18 int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lPCmdLine, int nCmdShow)
 19 {
 20     MyRegisterClass(hInstance);
 21     Create(hInstance,nCmdShow);
 22     ShowWindow(hWnd,nCmdShow);
 23     UpdateWindow(hWnd);
 24     return Run();
 25 }
 26 
 27 ATOM MyRegisterClass(HINSTANCE hInstance)
 28 {
 29     WNDCLASS wc;
 30     wc.style = 0;
 31     wc.lpfnWndProc = WndProc;
 32     wc.cbClsExtra = 0;
 33     wc.cbWndExtra = 0;
 34     wc.hInstance = hInstance;
 35     wc.hIcon = LoadIcon(NULL,IDI_APPLICATION);
 36     wc.hCursor = LoadCursor(NULL,IDC_ARROW);
 37     wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
 38     wc.lpszMenuName = NULL;
 39     wc.lpszClassName = lpszClassName;
 40     return RegisterClass(&wc);
 41 }
 42 
 43 BOOL Create(HINSTANCE hInstance, int nCmdShow)
 44 {
 45     hWnd = CreateWindow(lpszClassName,"Windows",WS_OVERLAPPEDWINDOW,400,300,180,160,NULL,NULL,hInstance,NULL);
 46     return TRUE;
 47 }
 48 
 49 int Run()
 50 {
 51     while (GetMessage(&msg, NULL, 0, 0))
 52     {
 53         TranslateMessage(&msg);
 54         DispatchMessage(&msg);
 55     }
 56     return msg.wParam;
 57 }
 58 
 59 LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 60 {
 61     switch (message)
 62     {
 63     case WM_LBUTTONDOWN:
 64         OnLButtonDown(hWnd,message,wParam,lParam);
 65         break;
 66     case WM_PAINT:
 67         OnPaint(hWnd,message,wParam,lParam);
 68         break;
 69     default:
 70         return DefWindowProc(hWnd,message,wParam,lParam);
 71     }
 72     return 0;
 73 }
 74 
 75 void OnLButtonDown(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 76 {
 77     ShowText = "Hello!";#include<windows.h>
 78 
 79 HINSTANCE hInst;
 80 HWND      hWnd;
 81 MSG          msg;
 82 char      lpszClassName[] = "窗口";
 83 char      *ShowText;
 84 
 85 ATOM      MyRegisterClass(HINSTANCE hInstance);
 86 BOOL      Create(HINSTANCE,int);
 87 int          Run();
 88 
 89 LRESULT   CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 90 void      OnLButtonDown(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
 91 void      OnPaint(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam);
 92 void      OnDestroy(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam);
 93 
 94 int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lPCmdLine, int nCmdShow)
 95 {
 96     MyRegisterClass(hInstance);
 97     Create(hInstance,nCmdShow);
 98     ShowWindow(hWnd,nCmdShow);
 99     UpdateWindow(hWnd);
100     return Run();
101 }
102 
103 ATOM MyRegisterClass(HINSTANCE hInstance)
104 {
105     WNDCLASS wc;
106     wc.style = 0;
107     wc.lpfnWndProc = WndProc;
108     wc.cbClsExtra = 0;
109     wc.cbWndExtra = 0;
110     wc.hInstance = hInstance;
111     wc.hIcon = LoadIcon(NULL,IDI_APPLICATION);
112     wc.hCursor = LoadCursor(NULL,IDC_ARROW);
113     wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
114     wc.lpszMenuName = NULL;
115     wc.lpszClassName = lpszClassName;
116     return RegisterClass(&wc);
117 }
118 
119 BOOL Create(HINSTANCE hInstance, int nCmdShow)
120 {
121     hWnd = CreateWindow(lpszClassName,"Windows",WS_OVERLAPPEDWINDOW,400,300,180,160,NULL,NULL,hInstance,NULL);
122     return TRUE;
123 }
124 
125 int Run()
126 {
127     while (GetMessage(&msg, NULL, 0, 0))
128     {
129         TranslateMessage(&msg);
130         DispatchMessage(&msg);
131     }
132     return msg.wParam;
133 }
134 
135 LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
136 {
137     switch (message)
138     {
139     case WM_LBUTTONDOWN:
140         OnLButtonDown(hWnd,message,wParam,lParam);
141         break;
142     case WM_PAINT:
143         OnPaint(hWnd,message,wParam,lParam);
144         break;
145     default:
146         return DefWindowProc(hWnd,message,wParam,lParam);
147     }
148     return 0;
149 }
150 
151 void OnLButtonDown(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
152 {
153     ShowText = "Hello!";
154     InvalidateRect(hWnd,NULL,1);
155 }
156 
157 void OnPaint(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
158 {
159     PAINTSTRUCT ps;
160     HDC hdc;
161     hdc = BeginPaint(hWnd,&ps);
162     TextOut(hdc,50,50,ShowText,6);
163     EndPaint(hWnd,&ps);
164 }
165 
166 void OnDestroy(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
167 {
168     PostQuitMessage(0);
169 }
170     InvalidateRect(hWnd,NULL,1);
171 }
172 
173 void OnPaint(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
174 {
175     PAINTSTRUCT ps;
176     HDC hdc;
177     hdc = BeginPaint(hWnd,&ps);
178     TextOut(hdc,50,50,ShowText,6);
179     EndPaint(hWnd,&ps);
180 }
181 
182 void OnDestroy(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
183 {
184     PostQuitMessage(0);
185 }

函数程序模块化