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[Solved] CXTPMarkupListBox crashes on empty list

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sdancer75 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sdancer75 Quote  Post ReplyReply Direct Link To This Post Topic: [Solved] CXTPMarkupListBox crashes on empty list
    Posted: 28 January 2020 at 3:49am
Version : 15.x 16.x and maybe newer versions

Symptoms : CXTPMarkupListBox and CXTPListBox crashes when the list box is empty and move mouse inside its client area.

Problem
Inside  void CXTPListBox::OnMouseMove(UINT nFlags, CPoint point)
the MFC function ItemFromPoint() returns a WORD (not signed) value of 65535 which means invalid or empty list. This value is returned to nHotItem.

int nHotItem = ItemFromPoint(point, bOutside) 

The signed int nHotItem is now 4 bytes so instead of converting the non signed word 65535 to -1, it remains 65535. After this, the code is calling 

BOOL CXTPMarkupListBox::OnWndMsg(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pResult) 

which in turn is calling an invalid item in  code below.

XTP_MARKUP_LISTITEM *pItem = reinterpret_cast<XTP_MARKUP_LISTITEM*>(GetItemDataPtr(m_nHotItem));

At this point the code crashes.

Solution

Inside void CXTPListBox::OnMouseMove(UINT nFlags, CPoint point)

declare nHotItem as short int instead of an int like below. 

short int nHotItem = ItemFromPoint(point, bOutside) 

Recompile all codejock libs and rebuild your project.
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Fredrik View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fredrik Quote  Post ReplyReply Direct Link To This Post Posted: 03 February 2020 at 12:23pm
Just looked at the code in version 18.x and 19 it's fixed there.
Windows 10, Visual Studio 20157, Toolkit Pro 18.3.0
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sdancer75 Quote  Post ReplyReply Direct Link To This Post Posted: 03 February 2020 at 2:44pm
Originally posted by Fredrik Fredrik wrote:

Just looked at the code in version 18.x and 19 it's fixed there.


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