Codejock Developer Community : [Solved] CXTPMarkupListBox crashes on empty list http://forum.codejock.com/ Copyright (c) 2006-2013 Web Wiz Forums - All Rights Reserved. Tue, 12 May 2026 21:03:38 +0000 Mon, 03 Feb 2020 14:44:40 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.04 360 forum.codejock.com/RSS_post_feed.asp?TID=23947 <![CDATA[Codejock Developer Community]]> http://forum.codejock.com/forum_images/codejock-logo.gif http://forum.codejock.com/ <![CDATA[[Solved] CXTPMarkupListBox crashes on empty list : Fredrik wrote:Just looked at...]]> http://forum.codejock.com/forum_posts.asp?TID=23947&PID=77610&title=solved-cxtpmarkuplistbox-crashes-on-empty-list#77610 Author: sdancer75
Subject: 23947
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.


Thanks]]> Mon, 03 Feb 2020 14:44:40 +0000 http://forum.codejock.com/forum_posts.asp?TID=23947&PID=77610&title=solved-cxtpmarkuplistbox-crashes-on-empty-list#77610 <![CDATA[[Solved] CXTPMarkupListBox crashes on empty list : Just looked at the code in version...]]> http://forum.codejock.com/forum_posts.asp?TID=23947&PID=77609&title=solved-cxtpmarkuplistbox-crashes-on-empty-list#77609 Author: Fredrik
Subject: 23947
Posted: 03 February 2020 at 12:23pm

Just looked at the code in version 18.x and 19 it's fixed there.]]> Mon, 03 Feb 2020 12:23:57 +0000 http://forum.codejock.com/forum_posts.asp?TID=23947&PID=77609&title=solved-cxtpmarkuplistbox-crashes-on-empty-list#77609 <![CDATA[[Solved] CXTPMarkupListBox crashes on empty list : Version : 15.x 16.x and maybe...]]> http://forum.codejock.com/forum_posts.asp?TID=23947&PID=77590&title=solved-cxtpmarkuplistbox-crashes-on-empty-list#77590 Author: sdancer75
Subject: 23947
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.
]]> Tue, 28 Jan 2020 03:49:11 +0000 http://forum.codejock.com/forum_posts.asp?TID=23947&PID=77590&title=solved-cxtpmarkuplistbox-crashes-on-empty-list#77590