我想显示一个对话框,通知用户应用程序正忙。为了避免阻塞主线程,我想使用std :: thread来显示对话框。请考虑以下代码:
InProcDlg inProcess;
std::thread t([ &inProcess ] {
inProcess.DoModal();
delete inProcess;
});
// wait till process fished
::PostMessage(inProcess.m_hWnd, WM_USER + 1, 0, 0);
if (t.joinable()){
t.join();
}
InProcDlg.cpp
BEGIN_MESSAGE_MAP(InProcDlg, CDialogEx)
...
ON_MESSAGE(WM_USER + 1, &InProcDlg::close)
END_MESSAGE_MAP()
LRESULT InProcDlg::close(WPARAM wParam, LPARAM lParam)
{
UNREFERENCED_PARAMETER(wParam, lParam);
EndDialog(1);
return 0;
}
运行此代码,对话框显示正确。该对话框也已关闭,但未显示主对话框,应用程序将挂起CreateRunDlgIndirect()
。尝试介入时,在设置一些断点时,主对话框会再次正确显示。很奇怪。对于我需要深入研究的任何建议,我会非常高兴。
在下一步中,我还想通过发送一个指示当前进程状态的整数来向用户显示该进程。
int *percent;
::PostMessage(inProcess.m_hWnd, WM_USER + 2, 0, reinterpret_cast<LPARAM>(percent));
在发送或发布消息之前,如何获取对话已存在的证据? 我使用的是Visual Studio 2013。
答案 0 :(得分:1)
我可以想到两种方法:
无模式对话
https://www.codeproject.com/Articles/1651/Tutorial-Modeless-Dialogs-with-MFC
用户线程(UI线程)
使用CWinThread为主UI线程(CWinApp)创建兄弟。最重要的是为CWinThread :: m_pMainWnd成员分配一个指向Dialog的指针。如果对话框是Modal,则在调用DoModal后立即返回FALSE,并返回TRUE for Modeless。
class CMainFrame : public CFrameWnd {
// pointer to thread
CWinThread* m_pUserThread;
}
启动帖子
m_pUserThread = AfxBeginThread(RUNTIME_CLASS(CUserThread), THREAD_PRIORITY_NORMAL, 0, CREATE_SUSPENDED );
m_pUserThread->m_bAutoDelete = TRUE;
m_pUserThread->ResumeThread();
headr file **
class CUserThread : public CWinThread
{
DECLARE_DYNCREATE(CUserThread)
public:
CUserThread();
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CUserThread)
public:
virtual BOOL InitInstance();
virtual int ExitInstance();
//}}AFX_VIRTUAL
protected:
virtual ~CUserThread();
// Generated message map functions
//{{AFX_MSG(CUserThread)
// NOTE - the ClassWizard will add and remove member functions here.
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
private:
CUserMsg* m_pDlg;
}
源文件
#define DO_MODAL
BOOL CUserThread::InitInstance()
{
#ifdef DO_MODAL
// create and assign Modeless dialog
CUserMsg dlg;
m_pMainWnd = &m_pDlg;
dlg.DoModal();
return FALSE;
#endif
#ifdnef DO_MODAL
// create and assign Modal dialog
m_pDlg = new CUserMsg();
m_pDlg->Create( IDD_USER_DLG, AfxGetMainWnd() );
m_pMainWnd = m_pDlg;
return TRUE;
#endif
}
int CUserThread::ExitInstance()
{
// check for null
m_pDlg->SendMessage( WM_CLOSE ) ;
delete m_pDlg;
return CWinThread::ExitInstance();
}
终止线程
// post quit message to thread
m_pUserThread->PostThreadMessage(WM_QUIT,0,0);
// wait until thread termineates
::WaitForSingleObject(m_pUserThread->m_hThread,INFINITE);
对于这两种方式,我强烈建议将对话框作为最顶层的窗口:
BOOL CLicenseGenDlg::OnInitDialog() {
CDialog::OnInitDialog();
// TODO: Add extra initialization here
SetWindowPos( &wndTopMost, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | WS_EX_TOPMOST );
return TRUE;
}