初识 Windows 消息机制——C语言调用计算器

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M.C

1. #include <windows.h>
   
2. #include <WinUser.h>
   
3. #include <stdio.h>
   
4. #include <stdlib.h>
   
5. 
   
6. int main(){
   
7. 
   
8.     BOOL opened; // 计算器是否已经成功打开的标志
   
9.     STARTUPINFO si ={sizeof(si)}; // 计算器启动信息
   
10.     PROCESS_INFORMATION pi; // 计算器进程信息
    
11.     HWND h1 = NULL; // 计算器窗口指针
    
12.     int i=0;
    
13.     BOOL postMsgResult;
    
14. 
    
15. 
    
16. 
    
17.     // 打开计算器
    
18.     opened = CreateProcess(NULL, "calc.exe", NULL, NULL, FALSE, 0, NULL,NULL, &si, &pi);
    
19.     if ( !opened ) {
    
20.         printf("无法打开计算器，错误码 = %d\n", GetLastError());
    
21.         return;
    
22.     }
    
23. 
    
24.     // 找到该窗口
    
25.     while ( h1 == NULL && i < 3 ){
    
26.          h1 = FindWindow(NULL, "计算器");
    
27.          if ( h1 == NULL ) {
    
28.             i ++;
    
29.             Sleep(1000);
    
30.          }
    
31.     }
    
32.     if ( h1 == NULL ) {
    
33.         printf("找不到已经打开的计算器，错误码 = %d\n", GetLastError());
    
34.         return;
    
35.     }
    
36.     for(i = 0; i < 3; i++){
    
37.         // keybd_event(0x39,0,KEYEVENTF_KEYUP,0); // FIXME
    
38.         // msgResult = SendMessage(h1,WM_CHAR,'4',0); // FIXME
    
39.         SetLastError(0);
    
40.        postMsgResult = PostMessage(h1,WM_CHAR,'1'+i,0);
    
41.         if ( i < 2 ){
    
42.             PostMessage(h1,WM_CHAR,'+',0);
    
43.         } else {
    
44.             PostMessage(h1,WM_CHAR,'=',0);
    
45.         }
    
46.         printf("result=%d, error=%d\n", postMsgResult, GetLastError());
    
47.         Sleep(1000);
    
48.     }
    
49. 
    
50.     system("Pause");
    
51.     return 0;
    
52. }