关于相应 CHeaderCtrl::OnChildNotify消息的问题

Question

在CListCtrl下是可以相应到该消息

但是在CMFCListCtrl下不能相应该消息

CListCtrl代码如下

void CMyListCtrl::PreSubclassWindow()
{

ModifyStyle(0, LVS_OWNERDRAWFIXED);
CListCtrl::PreSubclassWindow();
ModifyStyle(0, LVS_REPORT | LVS_SINGLESEL | LVS_SHOWSELALWAYS);
CHeaderCtrlEx *pHeader = (CHeaderCtrlEx*)this->GetHeaderCtrl();
m_ctrlHeader.SubclassWindow(pHeader->GetSafeHwnd());
}

是完全没有问题的

但是在CMFCListCtrl这个下就有问题

代码如下

void CMyListCtrl::PreSubclassWindow()
{

ModifyStyle(0, LVS_OWNERDRAWFIXED);
CMFCListCtrl::PreSubclassWindow();
ModifyStyle(0, LVS_REPORT | LVS_SINGLESEL | LVS_SHOWSELALWAYS);
CHeaderCtrlEx &pHeader = (CHeaderCtrlEx&)this->GetHeaderCtrl();
m_ctrlHeader.SubclassWindow(pHeader.GetSafeHwnd());
}

不知道什么原因，个人怀疑是GetSafeHwnd()在两个类里面不同导致的，求原因

Answer 1

IMPLEMENT_DYNAMIC(CHeaderCtrlEx, CMFCHeaderCtrl)
CHeaderCtrlEx::CHeaderCtrlEx()
{
	m_bLocked = FALSE;
}
CHeaderCtrlEx::~CHeaderCtrlEx()
{

}
BEGIN_MESSAGE_MAP(CHeaderCtrlEx, CMFCHeaderCtrl)
END_MESSAGE_MAP()
BOOL CHeaderCtrlEx::OnChildNotify(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pLResult)
{
	// TODO: 在此添加专用代码和/或调用基类
	HD_NOTIFY  *phdn = (HD_NOTIFY*)lParam;
	NMHDR& nmh = *(NMHDR*)lParam;
	if (nmh.code == HDN_BEGINTRACKA || nmh.code == HDN_BEGINTRACKW
		|| nmh.code == HDN_DIVIDERDBLCLICKA || nmh.code == HDN_DIVIDERDBLCLICKW)
	{
		CRect Rect;
		GetItemRect(phdn->iItem , Rect);
		if (Rect.Width() == 0)
		{
			return   *pLResult = TRUE;
		}  
	}
	return CMFCHeaderCtrl::OnChildNotify(message, wParam, lParam, pLResult);
}

IMPLEMENT_DYNAMIC(CMyListCtrl, CMFCListCtrl)
CMyListCtrl::CMyListCtrl()
{

}
CMyListCtrl::~CMyListCtrl()
{

}
BEGIN_MESSAGE_MAP(CMyListCtrl, CMFCListCtrl)
END_MESSAGE_MAP()
void CMyListCtrl::PreSubclassWindow()
{

	ModifyStyle(0, LVS_OWNERDRAWFIXED);
	CMFCListCtrl::PreSubclassWindow();
	ModifyStyle(0, LVS_REPORT | LVS_SINGLESEL | LVS_SHOWSELALWAYS);
	CHeaderCtrlEx &pHeader = (CHeaderCtrlEx&)this->GetHeaderCtrl();
	m_ctrlHeader.SubclassWindow(pHeader.GetSafeHwnd());
}
void CMyListCtrl::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{

}

Answer 2

class CHeaderCtrlEx : public CMFCHeaderCtrl
{
	DECLARE_DYNAMIC(CHeaderCtrlEx)
public:
	CHeaderCtrlEx();
	virtual ~CHeaderCtrlEx();

protected:
	DECLARE_MESSAGE_MAP()
public:
	virtual BOOL OnChildNotify(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pLResult);
	BOOL m_bLocked;
};

class CMyListCtrl : public CMFCListCtrl
{
	DECLARE_DYNAMIC(CMyListCtrl)
public:
	CMyListCtrl();
	virtual ~CMyListCtrl();

protected:
	DECLARE_MESSAGE_MAP()
	virtual void PreSubclassWindow();
	virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct);
public:
	CHeaderCtrlEx m_ctrlHeader;
};

Answer 3

Hi Hota_CT,

感谢在MSDN论坛发帖。

>>不知道什么原因，个人怀疑是GetSafeHwnd()在两个类里面不同导致的，求原因

CListCtrl::GetHeaderCtrl返回的是CHeaderCtrl类型的指针。

CHeaderCtrl* GetHeaderCtrl();

而CMFCListCtrl::GetHeaderCtrl返回的是CMFCHeaderCtrl类型的引用。

virtual CMFCHeaderCtrl& GetHeaderCtrl();

建议你改为以下代码。

CMFCHeaderCtrl &pHeader = (CMFCHeaderCtrl&)this->GetHeaderCtrl();
m_ctrlHeader.SubclassWindow(pHeader.GetSafeHwnd());

希望对你有所帮助。

Best Regards,
Sera Yu

---

MSDN Community Support<br/> Please remember to click &quot;Mark as Answer&quot; the responses that resolved your issue, and to click &quot;Unmark as Answer&quot; if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact <a href="mailto:[e-mail]">[e-mail]</a>.

Answer 4

目前我就是按照你说的这样做的，

还是有问题的 

pHeader.GetSafeHwnd()是空，导致的问题，

网上查阅资料，把子类化写在在CMFCListCtrl的OnCreate响应里面，

在OnCreate里面pHeader.GetSafeHwnd()不为空了，

调用SubclassWindow但是会有莫名的崩溃

求解决办法，谢谢

Answer 5

>>网上查阅资料，把子类化写在在CMFCListCtrl的OnCreate响应里面，

在OnCreate里面pHeader.GetSafeHwnd()不为空了，

调用SubclassWindow但是会有莫名的崩溃

该成员函数将Windows控件附加到“CWnd”对象，并替换窗口的** WndProc **和** AfxWndProc **函数。 该函数在“CWnd”对象中存储指向旧的** WndProc **的指针。所以请确保调用SubclassWindow函数时，窗口没有附加到其他MFC对象上。

你可以在调试模式下，查看Call Stack窗口，看看具体崩溃问题出在哪里。

或者使用Windbg工具，分析dmp文件。这里有篇文档，你可以参考一下。

https://docs.microsoft.com/en-us/windows-hardware/drivers/debugger/analyzing-a-user-mode-dump-file-with-windbg

希望对你有所帮助。

Best Regards,
Sera Yu

---

MSDN Community Support<br/> Please remember to click &quot;Mark as Answer&quot; the responses that resolved your issue, and to click &quot;Unmark as Answer&quot; if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact <a href="mailto:[e-mail]">[e-mail]</a>.