分析mfc中cdialog的子类对象如何知道自己是model还是modeless的.
DoModal源代码关键部分如下 1
if (CreateDlgIndirect(lpDialogTemplate,
2 CWnd::FromHandle(hWndParent), hInst))
3
{
4
if (m_nFlags & WF_CONTINUEMODAL)
5
{
6 // enter modal loop
7 DWORD dwFlags = MLF_SHOWONIDLE;
8 if (GetStyle() & DS_NOIDLEMSG)
9 dwFlags |= MLF_NOIDLEMSG;
10 VERIFY(RunModalLoop(dwFlags) == m_nModalResult);
11
}
if (CreateDlgIndirect(lpDialogTemplate,2
CWnd::FromHandle(hWndParent), hInst))3
{
4
if (m_nFlags & WF_CONTINUEMODAL)5
{
6
// enter modal loop7
DWORD dwFlags = MLF_SHOWONIDLE;8
if (GetStyle() & DS_NOIDLEMSG)9
dwFlags |= MLF_NOIDLEMSG;10
VERIFY(RunModalLoop(dwFlags) == m_nModalResult);11
}相对于CDialog的Create，DoModal多了一个RunModalLoop()这么一个消息循环（当然也有一些别的，比如在创建窗口之前disable父窗口）。因此关键在这个函数里，看进去，在文件VC\atlmfc\src\mfc\wincore.cpp里
1int CWnd::RunModalLoop(DWORD dwFlags)
2{
3 ASSERT(::IsWindow(m_hWnd)); // window must be created
4 ASSERT(!(m_nFlags & WF_MODALLOOP)); // window must not already be in modal state
5
6 // for tracking the idle time state
7 BOOL bIdle = TRUE;
8 LONG lIdleCount = 0;
9 BOOL bShowIdle = (dwFlags & MLF_SHOWONIDLE) && !(GetStyle() & WS_VISIBLE);
10 HWND hWndParent = ::GetParent(m_hWnd);
11 m_nFlags |= (WF_MODALLOOP|WF_CONTINUEMODAL);
12 MSG *pMsg = AfxGetCurrentMessage();
13
14 // acquire and dispatch messages until the modal state is done
15 for (;;)
16。。。。。。for内的消息之类的略掉。。。。
17ExitModal:
18 m_nFlags &= ~(WF_MODALLOOP|WF_CONTINUEMODAL);
19 return m_nModalResult;
20}
int CWnd::RunModalLoop(DWORD dwFlags)2
{3
ASSERT(::IsWindow(m_hWnd)); // window must be created4
ASSERT(!(m_nFlags & WF_MODALLOOP)); // window must not already be in modal state5
6
// for tracking the idle time state7
BOOL bIdle = TRUE;8
LONG lIdleCount = 0;9
BOOL bShowIdle = (dwFlags & MLF_SHOWONIDLE) && !(GetStyle() & WS_VISIBLE);10
HWND hWndParent = ::GetParent(m_hWnd);11
m_nFlags |= (WF_MODALLOOP|WF_CONTINUEMODAL);12
MSG *pMsg = AfxGetCurrentMessage();13
14
// acquire and dispatch messages until the modal state is done15
for (;;)16
。。。。。。for内的消息之类的略掉。。。。17
ExitModal:18
m_nFlags &= ~(WF_MODALLOOP|WF_CONTINUEMODAL);19
return m_nModalResult;20
}看到了吧，m_nFlags & WF_MODALLOOP就是用来判断本dialog是用DoModal还是直接Create创建的。
如果为true表示为model否则为modeless
注意：以上仅为现在MFC中CDialog中可用，其他lib，如WTL并不通用