[ wxwindows-Bugs-1478041 ] wxListCtrl and wxImageList bug

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Bugs item #1478041, was opened at 2006-04-27 22:26
Message generated for change (Settings changed) made by roebling
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Category: Generic
Group: Must fix
>Status: Closed
>Resolution: Fixed
Priority: 5
Private: No
Submitted By: Hartwig Wiesmann (hwiesmann)
Assigned to: Nobody/Anonymous (nobody)
Summary: wxListCtrl and wxImageList bug

Initial Comment:
Hi!

The code below does the following:

It creates a list in report view with one row that is first added, 
afterwards deleted and added again. One column of the list has got an 
image attached. There is always an image list attached to the list 
control.
When adding for the second time an element to the list, the code will 
crash (reason given after the code snippet).

Suppose I have got the following code:

wxListCtrl* ListCtrlPtr(new wxListCtrl(...));
wxImageList* ImageList(new wxImageList(16,16));

ImageList->Add(wxBitmap(...));
ListCtrl->AssignImageList(ImageList,wxIMAGE_LIST_SMALL);

// add for the first time an item:
ListCtrl->InsertItem(0,wxString());
ListCtrl->SetItemColumnImage(0,0,0);

// delete it again:
ListCtrl->DeleteItem(0);

// also delete the item from the image list:
ListCtrl->GetImageList(wxIMAGE_LIST_SMALL)->Remove(0);

// add an item again:
ListCtrl->InsertItem(0,wxString()); // ASSERT, BUG!!


The problem seems to be that 

wxListCtrl::InsertItem(int,wxString const&) initializes 
wxListItem::m_image with 0 to indicate a non-existing image while the 
internal method
wxListMainWindow::GetItemWidthWithImage(wxListItem*) compares 
wxListItem::m_image with -1 to check if an image exists.

The reason why it did not crash in the first case is that the image list 
had an element while in the second case the image list is empty.
The code does NOT crash if there is a rule that empty image lists are 
not allowed. But this does not make sense.

Solution for this bug: set wxListItem::m_image to -1

(but I do not know if any function check the variable against 0)

Hartwig
 

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Comment By: Hartwig Wiesmann (hwiesmann)
Date: 2007-06-04 05:38

Message:
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Originator: YES

Can you please close this bug as it seems to be solved, now (see 1727909).
Actually, I did not know that I have submitted this bug earlier.

Hartwig


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Comment By: Hartwig Wiesmann (hwiesmann)
Date: 2006-04-30 15:58

Message:
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Hi,

I do not know what wxMSW does because I am using only MacOSX.

Hartwig


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Comment By: Robert Roebling (roebling)
Date: 2006-04-30 10:20

Message:
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user_id=77100

What does wxMSW do here? If you e.g. add an item without an
image to an wxMSW wxListCtrl and then query it image index,
will it return -1?

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