VC根据进程ID获得主窗口句柄（不是进程句柄）

typedef struct
{
 HWND hWnd;
 DWORD dwPid;
}WNDINFO;

BOOL CALLBACK EnumWindowsProc(HWND hWnd, LPARAM lParam)
{
 WNDINFO* pInfo = (WNDINFO*)lParam;
 DWORD dwProcessId = 0;
 GetWindowThreadProcessId(hWnd, &dwProcessId);

 if(dwProcessId == pInfo->dwPid)
 {
  pInfo->hWnd = hWnd;
  return FALSE;
 }
 return TRUE;
}

HWND GetHwndByProcessId(DWORD dwProcessId)
{
 WNDINFO info = {0};
 info.hWnd = NULL;
 info.dwPid = dwProcessId;
 EnumWindows(EnumWindowsProc, (LPARAM)&info);
 return info.hWnd;
}