初识 Windows 消息机制——C语言调用计算器

 ZZ.zip  



M.C

#include <windows.h>
#include <WinUser.h>
#include <stdio.h>
#include <stdlib.h>

int main(){

    BOOL opened;                     // 计算器是否已经成功打开的标志
    STARTUPINFO si ={sizeof(si)};    // 计算器启动信息
    PROCESS_INFORMATION pi;          // 计算器进程信息
    HWND h1 = NULL;                  // 计算器窗口指针
    int i=0;
    BOOL postMsgResult;



    // 打开计算器
    opened = CreateProcess(NULL, "calc.exe", NULL, NULL, FALSE, 0, NULL,NULL, &si, &pi);
    if ( !opened ) {
        printf("无法打开计算器，错误码 = %d\n", GetLastError());
        return;
    }

    // 找到该窗口
    while ( h1 == NULL && i < 3 ){
         h1 = FindWindow(NULL, "计算器");
         if ( h1 == NULL ) {
            i ++;
            Sleep(1000);
         }
    }
    if ( h1 == NULL ) {
        printf("找不到已经打开的计算器，错误码 = %d\n", GetLastError());
        return;
    }
    for(i = 0; i < 3; i++){
        // keybd_event(0x39,0,KEYEVENTF_KEYUP,0);     // FIXME
        // msgResult = SendMessage(h1,WM_CHAR,'4',0); // FIXME
        SetLastError(0);
       postMsgResult =  PostMessage(h1,WM_CHAR,'1'+i,0);
        if ( i < 2 ){
            PostMessage(h1,WM_CHAR,'+',0);
        } else {
            PostMessage(h1,WM_CHAR,'=',0);
        }
        printf("result=%d, error=%d\n", postMsgResult, GetLastError());
        Sleep(1000);
    }

    system("Pause");
    return 0;
}