Edit控件显示内容

 

用Edit控件接收消息并显示LPARAM内容。

 

环境：EVC4.0

 

过程：

 1、创建一个典型的“Hello World”的WCE Application;

       ( File -> new -> Projects -> choose "WCE Application" , enter the project name -> default choose "a typical Hello world project ")

2、添加及修改以下代码

1. //添加定义
2. #define ID_EDIT        301
3. #define ID_COMMTIME    302
5. //定义编辑框控件为全局变量
6. HWND g_hWndShow;
7. void Test()
8. {
9.     int total;
10.     int start;
11.     int end;
12.     LPTSTR  szBuff = new TCHAR[64];
13.     start = GetTickCount();
14.     for (i = 0; i < 100000; i++)
15.     {
16.        
17.     }
18.     end = GetTickCount();
19.     total = end - start;
20.     wsprintf(szBuff, L"Test Time: %d /r/n", total);
21.     SendMessage(g_hWndShow, EM_REPLACESEL, 0, (LPARAM)szBuff);    
22. }
25. //调用该函数
26. LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
27. {
28.     HDC hdc;
29.     int wmId, wmEvent;
30.     PAINTSTRUCT ps;
31.     TCHAR szHello[MAX_LOADSTRING];
32.         HWND hWndCOMM;
33.         UCHAR temp[64];
35.     switch (message) 
36.     {
37.         case WM_COMMAND:
38.             wmId    = LOWORD(wParam); 
39.             wmEvent = HIWORD(wParam); 
40.             // Parse the menu selections:
41.             switch (wmId)
42.             {
43.             
44.                 case IDM_HELP_ABOUT:
45.                    DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
46.                    break;
47.                 case IDM_FILE_EXIT:
48.                    DestroyWindow(hWnd);
49.                    break;              
50.                 case ID_COMMTIME:
51.                     Test();  //调用Test函数
52.                 break;
53.                 default:
54.                    return DefWindowProc(hWnd, message, wParam, lParam);
55.             }
56.             break;
57.         case WM_CREATE:
58.             hwndCB = CommandBar_Create(hInst, hWnd, 1);         
59.             CommandBar_InsertMenubar(hwndCB, hInst, IDM_MENU, 0);
60.             CommandBar_AddAdornments(hwndCB, 0, 0);
62.             g_hWndShow = CreateWindow(TEXT("edit"),
63.                 NULL,
64.                 WS_VISIBLE | WS_CHILD | ES_AUTOHSCROLL | ES_AUTOVSCROLL | ES_MULTILINE | ES_LEFT | WS_BORDER,
65.                 50,
66.                 50,
67.                 380,
68.                 200,
69.                 hWnd,
70.                 (HMENU)ID_EDIT,
71.                 hInst,
72.                 NULL
73.                 );
75.                 hWndCOMM = CreateWindow(TEXT("button"),
76.                 TEXT("COMTime"),
77.                 WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON,
78.                 190,
79.                 340,
80.                 100,
81.                 30,
82.                 hWnd,
83.                 (HMENU)ID_COMMTIME,
84.                 hInst,
85.                 NULL);
87.                 break;
88.         case WM_PAINT:
89.             RECT rt;
90.             hdc = BeginPaint(hWnd, &ps);
91.             GetClientRect(hWnd, &rt);
92. //          LoadString(hInst, IDS_HELLO, szHello, MAX_LOADSTRING);
93. //          DrawText(hdc, szHello, _tcslen(szHello), &rt, 
94. //              DT_SINGLELINE | DT_VCENTER | DT_CENTER);
95.             EndPaint(hWnd, &ps);
96.             break;
97.         case WM_DESTROY:
98.             CommandBar_Destroy(hwndCB);
99.             PostQuitMessage(0);
100.             break;
101.                 default:
102.             return DefWindowProc(hWnd, message, wParam, lParam);
103.    }
104.    return 0;
105. }

 

错误：

SendMessage(g_hWndShow, EM_REPLACESEL, 0, (LPARAM) total);

 

刚开始是这样写的，结果编辑框没有显示内容。原因为：

在一般情况下，lParam是一个指针，它指向的数据类型有三种：长整形、自定义数据结构类型、字符串类型。

需要将total转换为字符串才可以正常显示。使用wsprintf把total的内容赋给了数组szBuff。

改完后可以正常显示了。

 

EM_REPLACESEL   用指定文本替换编辑控件中的当前选定内容

WM_SETTEXT       会把原内容清空