两个窗口之间的通信，你能想到什么

最新推荐文章于 2024-05-19 18:00:00 发布

原创最新推荐文章于 2024-05-19 18:00:00 发布 · 916 阅读

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#mfc #thread #通信 #Cevent

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本文介绍了一种通过创建监听事件线程实现组件间通信的方法。A类通过创建线程实时监听B类触发的事件，并更新UI显示。该方案适用于需要实时响应特定事件的应用场景。

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我首先想到发消息，SendMessage也好，PostMessage也好。

还有什么呢，直接加个B类变量作为A的成员变量，之后进行操作。

还有一种方法，就是开个监听事件线程,以A实时响应B的操作为例：

A.h

protected:
HANDLE m_hListenCorrAnsThread;

static DWORD WINAPI ListenCorrAnswersThread(LPVOID lParam);
BOOL StartThreadListenCorrAnswer();

public:
static CEvent s_evtCorrAnswer; //用于监视学生答案是否提交
static CString s_sCorrAnswer;
static int s_nCorrPercent;

A.cpp

CString A::s_sCorrAnswer = "";
int A::s_nCorrPercent = 0;
CEvent A::s_evtCorrAnswer;

void A::OnInitialUpdate()
{
......

if (!StartThreadListenCorrAnswer())
{
MessageBox("开启正确答案监听线程失败！");
}

// TODO: Add your specialized code here and/or call the base class
}

/******************************************************************
* Function         :开启监听正确答案线程
* Input Parameters :
* Output Parameters:
* Return Value     :
* Created By       :yal 2013.08.29
*******************************************************************/
BOOL A::StartThreadListenCorrAnswer()
{
LOG(_T("启动客观题统计监听正确答案线程！\n"));

CWinThread* hThread = ::AfxBeginThread((AFX_THREADPROC)A::ListenCorrAnswersThread, (LPVOID)this);

m_hListenCorrAnsThread = hThread->m_hThread;

return (m_hListenCorrAnsThread != NULL);
}
/******************************************************************
* Function         :监听正确答案处理函数
* Input Parameters :
* Output Parameters:
* Return Value     :
* Created By       :yal 2013.08.29
*******************************************************************/
DWORD WINAPI A::ListenCorrAnswersThread(LPVOID lParam)
{
TRACE(_T("CObjectiveStatisticsView::ListenCorrAnswersThread\n"));
CObjectiveStatisticsView* pObjectView = (CObjectiveStatisticsView*)lParam;

while (TRUE)
{
  if (WAIT_FAILED == ::WaitForSingleObject(s_evtCorrAnswer.m_hObject, INFINITE))
  {
   DWORD dError = ::GetLastError();
   LOG("WaitForSingleObject函数出现错误，错误代码：%d，程序退出", dError);
   return 1;
  }

  if(!s_sCorrAnswer.IsEmpty())
  {
   //得到正确率百分比区域
   CDC* pDc = pObjectView->GetDlgItem(IDC_OBJECTIVE_PERCENTAGE_CORRECT)->GetDC();
   CRect rect;
   pObjectView->GetDlgItem(IDC_OBJECTIVE_PERCENTAGE_CORRECT)->GetClientRect(&rect);
   pObjectView->InvalidateRect(&rect,TRUE);
   pObjectView->UpdateWindow();
   //设置字体
   CFont m_Font;
   m_Font.CreateFont(100,0,0,0,FW_NORMAL,FALSE,FALSE,0,
    ANSI_CHARSET,OUT_DEFAULT_PRECIS,CLIP_DEFAULT_PRECIS,
    DEFAULT_QUALITY,FF_SWISS,"Arial");

   //CFont *pOldFont = (CFont*)pDc->SelectObject(&m_Font);
   pDc->SelectObject(&m_Font);
   pDc->SetTextColor(RGB(94,179,19));
   pDc->SetBkMode(TRANSPARENT);
   //画百分比
   CString sPercent;
   sPercent.Format("%d",s_nCorrPercent);
   if (s_nCorrPercent >= 100)
   {
    pDc->DrawText(sPercent, CRect(2,25,60,128), DT_NOCLIP);
   }
   else if (s_nCorrPercent >= 10)
   {
    pDc->DrawText(sPercent, CRect(25,25,60,128), DT_NOCLIP);
   }
   else
   {
    pDc->DrawText(sPercent, CRect(50,25,60,128), DT_NOCLIP);
   }
  }
}
return 0;
}