A list control presents lists in a number of formats: list view, report view, icon view and small icon view. In any case, elements are numbered from zero. For all these modes, the items are stored in the control and must be added to it using InsertItem method.
A special case of report view quite different from the other modes of the list control is a virtual control in which the items data (including text, images and attributes) is managed by the main program and is requested by the control itself only when needed which allows to have controls with millions of items without consuming much memory. To use virtual list control you must use SetItemCount first and overload at least OnGetItemText (and optionally OnGetItemImage and OnGetItemAttr) to return the information about the items when the control requests it. Virtual list control can be used as a normal one except that no operations which can take time proportional to the number of items in the control happen -- this is required to allow having a practically infinite number of items. For example, in a multiple selection virtual list control, the selections won't be sent when many items are selected at once because this could mean iterating over all the items.
Using many of wxListCtrl features is shown in the corresponding sample.
To intercept events from a list control, use the event table macros described in wxListEvent.
Derived from
wxControl
wxWindow
wxEvtHandler
wxObject
Include files
<wx/listctrl.h>
Window styles
wxLC_LIST | Multicolumn list view, with optional small icons. Columns are computed automatically, i.e. you don't set columns as in wxLC_REPORT. In other words, the list wraps, unlike a wxListBox. |
wxLC_REPORT | Single or multicolumn report view, with optional header. |
wxLC_VIRTUAL | The application provides items text on demand. May only be used with wxLC_REPORT. |
wxLC_ICON | Large icon view, with optional labels. |
wxLC_SMALL_ICON | Small icon view, with optional labels. |
wxLC_ALIGN_TOP | Icons align to the top. Win32 default, Win32 only. |
wxLC_ALIGN_LEFT | Icons align to the left. |
wxLC_AUTOARRANGE | Icons arrange themselves. Win32 only. |
wxLC_EDIT_LABELS | Labels are editable: the application will be notified when editing starts. |
wxLC_NO_HEADER | No header in report mode. |
wxLC_SINGLE_SEL | Single selection (default is multiple). |
wxLC_SORT_ASCENDING | Sort in ascending order (must still supply a comparison callback in SortItems. |
wxLC_SORT_DESCENDING | Sort in descending order (must still supply a comparison callback in SortItems. |
wxLC_HRULES | Draws light horizontal rules between rows in report mode. |
wxLC_VRULES | Draws light vertical rules between columns in report mode. |
See also window styles overview.
Event handling
To process input from a list control, use these event handler macros to direct input to member functions that take a wxListEvent argument.
EVT_LIST_BEGIN_DRAG(id, func) | Begin dragging with the left mouse button. |
EVT_LIST_BEGIN_RDRAG(id, func) | Begin dragging with the right mouse button. |
EVT_LIST_BEGIN_LABEL_EDIT(id, func) | Begin editing a label. This can be prevented by calling Veto(). |
EVT_LIST_END_LABEL_EDIT(id, func) | Finish editing a label. This can be prevented by calling Veto(). |
EVT_LIST_DELETE_ITEM(id, func) | Delete an item. |
EVT_LIST_DELETE_ALL_ITEMS(id, func) | Delete all items. |
EVT_LIST_ITEM_SELECTED(id, func) | The item has been selected. |
EVT_LIST_ITEM_DESELECTED(id, func) | The item has been deselected. |
EVT_LIST_ITEM_ACTIVATED(id, func) | The item has been activated (ENTER or double click). |
EVT_LIST_ITEM_FOCUSED(id, func) | The currently focused item has changed. |
EVT_LIST_ITEM_MIDDLE_CLICK(id, func) | The middle mouse button has been clicked on an item. |
EVT_LIST_ITEM_RIGHT_CLICK(id, func) | The right mouse button has been clicked on an item. |
EVT_LIST_KEY_DOWN(id, func) | A key has been pressed. |
EVT_LIST_INSERT_ITEM(id, func) | An item has been inserted. |
EVT_LIST_COL_CLICK(id, func) | A column (m_col) has been left-clicked. |
EVT_LIST_COL_RIGHT_CLICK(id, func) | A column (m_col) has been right-clicked. |
EVT_LIST_COL_BEGIN_DRAG(id, func) | The user started resizing a column - can be vetoed. |
EVT_LIST_COL_DRAGGING(id, func) | The divider between columns is being dragged. |
EVT_LIST_COL_END_DRAG(id, func) | A column has been resized by the user. |
EVT_LIST_CACHE_HINT(id, func) | Prepare cache for a virtual list control |
wxListCtrl overview, wxListView, wxListBox, wxTreeCtrl, wxImageList, wxListEvent, wxListItem
Members
wxListCtrl::wxListCtrl
wxListCtrl::~wxListCtrl
wxListCtrl::Arrange
wxListCtrl::AssignImageList
wxListCtrl::ClearAll
wxListCtrl::Create
wxListCtrl::DeleteAllItems
wxListCtrl::DeleteColumn
wxListCtrl::DeleteItem
wxListCtrl::EditLabel
wxListCtrl::EnsureVisible
wxListCtrl::FindItem
wxListCtrl::GetColumn
wxListCtrl::GetColumnCount
wxListCtrl::GetColumnWidth
wxListCtrl::GetCountPerPage
wxListCtrl::GetEditControl
wxListCtrl::GetImageList
wxListCtrl::GetItem
wxListCtrl::GetItemBackgroundColour
wxListCtrl::GetItemCount
wxListCtrl::GetItemData
wxListCtrl::GetItemFont
wxListCtrl::GetItemPosition
wxListCtrl::GetItemRect
wxListCtrl::GetItemSpacing
wxListCtrl::GetItemState
wxListCtrl::GetItemText
wxListCtrl::GetItemTextColour
wxListCtrl::GetNextItem
wxListCtrl::GetSelectedItemCount
wxListCtrl::GetTextColour
wxListCtrl::GetTopItem
wxListCtrl::GetViewRect
wxListCtrl::HitTest
wxListCtrl::InsertColumn
wxListCtrl::InsertItem
wxListCtrl::OnGetItemAttr
wxListCtrl::OnGetItemImage
wxListCtrl::OnGetItemText
wxListCtrl::RefreshItem
wxListCtrl::RefreshItems
wxListCtrl::ScrollList
wxListCtrl::SetBackgroundColour
wxListCtrl::SetColumn
wxListCtrl::SetColumnWidth
wxListCtrl::SetImageList
wxListCtrl::SetItem
wxListCtrl::SetItemBackgroundColour
wxListCtrl::SetItemCount
wxListCtrl::SetItemData
wxListCtrl::SetItemFont
wxListCtrl::SetItemImage
wxListCtrl::SetItemColumnImage
wxListCtrl::SetItemPosition
wxListCtrl::SetItemState
wxListCtrl::SetItemText
wxListCtrl::SetItemTextColour
wxListCtrl::SetSingleStyle
wxListCtrl::SetTextColour
wxListCtrl::SetWindowStyleFlag
wxListCtrl::SortItems
wxListCtrl()
Default constructor.
wxListCtrl(wxWindow* parent, wxWindowID id, const wxPoint& pos = wxDefaultPosition, const wxSize& size = wxDefaultSize, long style = wxLC_ICON, const wxValidator& validator = wxDefaultValidator, const wxString& name = wxListCtrlNameStr)
Constructor, creating and showing a list control.
Parameters
parent
id
pos
size
style
validator
name
See also
wxListCtrl::Create, wxValidator
void ~wxListCtrl()
Destructor, destroying the list control.
bool Arrange(int flag = wxLIST_ALIGN_DEFAULT)
Arranges the items in icon or small icon view. This only has effect on Win32. flag is one of:
wxLIST_ALIGN_DEFAULT | Default alignment. |
wxLIST_ALIGN_LEFT | Align to the left side of the control. |
wxLIST_ALIGN_TOP | Align to the top side of the control. |
wxLIST_ALIGN_SNAP_TO_GRID | Snap to grid. |
void AssignImageList(wxImageList* imageList, int which)
Sets the image list associated with the control and takes ownership of it (i.e. the control will, unlike when using SetImageList, delete the list when destroyed). which is one of wxIMAGE_LIST_NORMAL, wxIMAGE_LIST_SMALL, wxIMAGE_LIST_STATE (the last is unimplemented).
See also
void ClearAll()
Deletes all items and all columns.
bool Create(wxWindow* parent, wxWindowID id, const wxPoint& pos = wxDefaultPosition, const wxSize& size = wxDefaultSize, long style = wxLC_ICON, const wxValidator& validator = wxDefaultValidator, const wxString& name = wxListCtrlNameStr)
Creates the list control. See wxListCtrl::wxListCtrl for further details.
bool DeleteAllItems()
Deletes all the items in the list control.
NB: This function does not send the wxEVT_COMMAND_LIST_DELETE_ITEM event because deleting many items from the control would be too slow then (unlike DeleteItem).
bool DeleteColumn(int col)
Deletes a column.
bool DeleteItem(long item)
Deletes the specified item. This function sends the wxEVT_COMMAND_LIST_DELETE_ITEM event for the item being deleted.
See also: DeleteAllItems
void EditLabel(long item)
Starts editing the label of the given item. This function generates a EVT_LIST_BEGIN_LABEL_EDIT event which can be vetoed so that no text control will appear for in-place editing.
If the user changed the label (i.e. s/he does not press ESC or leave the text control without changes, a EVT_LIST_END_LABEL_EDIT event will be sent which can be vetoed as well.
bool EnsureVisible(long item)
Ensures this item is visible.
long FindItem(long start, const wxString& str, const bool partial = false)
Find an item whose label matches this string, starting from start or the beginning if start is -1.
long FindItem(long start, long data)
Find an item whose data matches this data, starting from start or the beginning if 'start' is -1.
long FindItem(long start, const wxPoint& pt, int direction)
Find an item nearest this position in the specified direction, starting from start or the beginning if start is -1.
wxPython note: In place of a single overloaded method name, wxPython implements the following methods:
FindItem(start, str, partial=false) | |
FindItemData(start, data) | |
FindItemAtPos(start, point, direction) |
wxPerl note: In wxPerl there are three methods instead of a single overloaded method:
FindItem( start, str, partial = false ) | |
FindItemData( start, data ) | |
FindItemAtPos( start, point, direction ) |
bool GetColumn(int col, wxListItem& item) const
Gets information about this column. See wxListCtrl::SetItem for more information.
wxPerl note: In wxPerl this method takes only the col parameter and returns a Wx::ListItem ( or undef ).
int GetColumnCount() const
Returns the number of columns.
int GetColumnWidth(int col) const
Gets the column width (report view only).
int GetCountPerPage() const
Gets the number of items that can fit vertically in the visible area of the list control (list or report view) or the total number of items in the list control (icon or small icon view).
wxTextCtrl * GetEditControl() const
Returns the edit control being currently used to edit a label. Returns NULL if no label is being edited.
NB: It is currently only implemented for wxMSW.
wxImageList* GetImageList(int which) const
Returns the specified image list. which may be one of:
wxIMAGE_LIST_NORMAL | The normal (large icon) image list. |
wxIMAGE_LIST_SMALL | The small icon image list. |
wxIMAGE_LIST_STATE | The user-defined state image list (unimplemented). |
bool GetItem(wxListItem& info) const
Gets information about the item. See wxListCtrl::SetItem for more information.
You must call info.SetId() to the ID of item you're interested in before calling this method.
wxPython note: The wxPython version of this method takes an integer parameter for the item ID, an optional integer for the column number, and returns the wxListItem object.
wxPerl note: In wxPerl this method takes as parameter the ID of the item and ( optionally ) the column, and returns a Wx::ListItem object.
wxColour GetItemBackgroundColour(long item) const
Returns the colour for this item. If the item has no specific colour, returns an invalid colour (and not the default background control of the control itself).
See also
int GetItemCount() const
Returns the number of items in the list control.
long GetItemData(long item) const
Gets the application-defined data associated with this item.
wxFont GetItemFont(long item) const
Returns the item's font.
bool GetItemPosition(long item, wxPoint& pos) const
Returns the position of the item, in icon or small icon view.
wxPython note: The wxPython version of this method accepts only the item ID and returns the wxPoint.
wxPerl note: In wxPerl this method takes only the item parameter and returns a Wx::Point ( or undef ).
bool GetItemRect(long item, wxRect& rect, int code = wxLIST_RECT_BOUNDS) const
Returns the rectangle representing the item's size and position, in physical coordinates.
code is one of wxLIST_RECT_BOUNDS, wxLIST_RECT_ICON, wxLIST_RECT_LABEL.
wxPython note: The wxPython version of this method accepts only the item ID and code and returns the wxRect.
wxPerl note: In wxPerl this method takes only the item parameter and returns a Wx::Rect ( or undef ).
wxSize GetItemSpacing() const
Retrieves the spacing between icons in pixels: horizontal spacing is returned as x component of the wxSize object and the vertical spacing as its y component.
int GetItemState(long item, long stateMask) const
Gets the item state. For a list of state flags, see wxListCtrl::SetItem.
The stateMask indicates which state flags are of interest.
wxString GetItemText(long item) const
Gets the item text for this item.
wxColour GetItemTextColour(long item) const
Returns the colour for this item. If the item has no specific colour, returns an invalid colour (and not the default foreground control of the control itself as this wouldn't allow distinguishing between items having the same colour as the current control foreground and items with default colour which, hence, have always the same colour as the control).
long GetNextItem(long item, int geometry = wxLIST_NEXT_ALL, int state = wxLIST_STATE_DONTCARE) const
Searches for an item with the given geometry or state, starting from item but excluding the item itself. If item is -1, the first item that matches the specified flags will be returned.
Returns the first item with given state following item or -1 if no such item found.
This function may be used to find all selected items in the control like this:
long item = -1; for ( ;; ) { item = listctrl->GetNextItem(item, wxLIST_NEXT_ALL, wxLIST_STATE_SELECTED); if ( item == -1 ) break; // this item is selected - do whatever is needed with it wxLogMessage("Item %ld is selected."), item); }geometry can be one of:
wxLIST_NEXT_ABOVE | Searches for an item above the specified item. |
wxLIST_NEXT_ALL | Searches for subsequent item by index. |
wxLIST_NEXT_BELOW | Searches for an item below the specified item. |
wxLIST_NEXT_LEFT | Searches for an item to the left of the specified item. |
wxLIST_NEXT_RIGHT | Searches for an item to the right of the specified item. |
NB: this parameter is only supported by wxMSW currently and ignored on other platforms.
state can be a bitlist of the following:
wxLIST_STATE_DONTCARE | Don't care what the state is. |
wxLIST_STATE_DROPHILITED | The item indicates it is a drop target. |
wxLIST_STATE_FOCUSED | The item has the focus. |
wxLIST_STATE_SELECTED | The item is selected. |
wxLIST_STATE_CUT | The item is selected as part of a cut and paste operation. |
int GetSelectedItemCount() const
Returns the number of selected items in the list control.
wxColour GetTextColour() const
Gets the text colour of the list control.
long GetTopItem() const
Gets the index of the topmost visible item when in list or report view.
wxRect GetViewRect() const
Returns the rectangle taken by all items in the control. In other words, if the controls client size were equal to the size of this rectangle, no scrollbars would be needed and no free space would be left.
Note that this function only works in the icon and small icon views, not in list or report views (this is a limitation of the native Win32 control).
long HitTest(const wxPoint& point, int& flags)
Determines which item (if any) is at the specified point, giving details in flags. Returns index of the item or wxNOT_FOUND if no item is at the specified point. flags will be a combination of the following flags:
wxLIST_HITTEST_ABOVE | Above the client area. |
wxLIST_HITTEST_BELOW | Below the client area. |
wxLIST_HITTEST_NOWHERE | In the client area but below the last item. |
wxLIST_HITTEST_ONITEMICON | On the bitmap associated with an item. |
wxLIST_HITTEST_ONITEMLABEL | On the label (string) associated with an item. |
wxLIST_HITTEST_ONITEMRIGHT | In the area to the right of an item. |
wxLIST_HITTEST_ONITEMSTATEICON | On the state icon for a tree view item that is in a user-defined state. |
wxLIST_HITTEST_TOLEFT | To the right of the client area. |
wxLIST_HITTEST_TORIGHT | To the left of the client area. |
wxLIST_HITTEST_ONITEM | Combination of wxLIST_HITTEST_ONITEMICON, wxLIST_HITTEST_ONITEMLABEL, wxLIST_HITTEST_ONITEMSTATEICON. |
wxPython note: A tuple of values is returned in the wxPython version of this method. The first value is the item id and the second is the flags value mentioned above.
wxPerl note: In wxPerl this method only takes the point parameter and returns a 2-element list ( item, flags ).
long InsertColumn(long col, wxListItem& info)
long InsertColumn(long col, const wxString& heading, int format = wxLIST_FORMAT_LEFT, int width = -1)
For report view mode (only), inserts a column. For more details, see wxListCtrl::SetItem.
wxPython note: In place of a single overloaded method name, wxPython implements the following methods:
InsertColumn(col, heading, format=wxLIST_FORMAT_LEFT, width=-1) | Creates a column using a header string only. |
InsertColumnItem(col, item) | Creates a column using a wxListItem. |
long InsertItem(wxListItem& info)
Inserts an item, returning the index of the new item if successful, -1 otherwise.
long InsertItem(long index, const wxString& label)
Inserts a string item.
long InsertItem(long index, int imageIndex)
Inserts an image item.
long InsertItem(long index, const wxString& label, int imageIndex)
Insert an image/string item.
Parameters
info
index
label
imageIndex
wxPython note: In place of a single overloaded method name, wxPython implements the following methods:
InsertItem(item) | Inserts an item using a wxListItem. |
InsertStringItem(index, label) | Inserts a string item. |
InsertImageItem(index, imageIndex) | Inserts an image item. |
InsertImageStringItem(index, label, imageIndex) | Insert an image/string item. |
wxPerl note: In wxPerl there are four methods instead of a single overloaded method:
InsertItem( item ) | Inserts a Wx::ListItem |
InsertStringItem( index, label ) | Inserts a string item |
InsertImageItem( index, imageIndex ) | Inserts an image item |
InsertImageStringItem( index, label, imageIndex ) | Inserts an item with a string and an image |
virtual wxListItemAttr * OnGetItemAttr(long item) const
This function may be overloaded in the derived class for a control with wxLC_VIRTUAL style. It should return the attribute for the for the specified item or NULL to use the default appearance parameters.
wxListCtrl will not delete the pointer or keep a reference of it. You can return the same wxListItemAttr pointer for every OnGetItemAttr call.
The base class version always returns NULL.
See also
virtual int OnGetItemImage(long item)
This function must be overloaded in the derived class for a control with wxLC_VIRTUAL style having an image list (if the control doesn't have an image list, it is not necessary to overload it). It should return the index of the items image in the controls image list or -1 for no image. In a control with wxLC_REPORT style, OnGetItemImage only gets called for the first column of each line.
The base class version always returns -1.
See also
virtual wxString OnGetItemText(long item, long column) const
This function must be overloaded in the derived class for a control with wxLC_VIRTUAL style. It should return the string containing the text of the given column for the specified item.
See also
SetItemCount,
OnGetItemImage,
OnGetItemAttr
void RefreshItem(long item)
Redraws the given item. This is only useful for the virtual list controls as without calling this function the displayed value of the item doesn't change even when the underlying data does change.
See also
void RefreshItems(long itemFrom, long itemTo)
Redraws the items between itemFrom and itemTo. The starting item must be less than or equal to the ending one.
Just as RefreshItem this is only useful for virtual list controls.
bool ScrollList(int dx, int dy)
Scrolls the list control. If in icon, small icon or report view mode, dx specifies the number of pixels to scroll. If in list view mode, dx specifies the number of columns to scroll. dy always specifies the number of pixels to scroll vertically.
NB: This method is currently only implemented in the Windows version.
void SetBackgroundColour(const wxColour& col)
Sets the background colour (GetBackgroundColour already implicit in wxWindow class).
bool SetColumn(int col, wxListItem& item)
Sets information about this column. See wxListCtrl::SetItem for more information.
bool SetColumnWidth(int col, int width)
Sets the column width.
width can be a width in pixels or wxLIST_AUTOSIZE (-1) or wxLIST_AUTOSIZE_USEHEADER (-2). wxLIST_AUTOSIZE will resize the column to the length of its longest item. wxLIST_AUTOSIZE_USEHEADER will resize the column to the length of the header (Win32) or 80 pixels (other platforms).
In small or normal icon view, col must be -1, and the column width is set for all columns.
void SetImageList(wxImageList* imageList, int which)
Sets the image list associated with the control. which is one of wxIMAGE_LIST_NORMAL, wxIMAGE_LIST_SMALL, wxIMAGE_LIST_STATE (the last is unimplemented).
This method does not take ownership of the image list, you have to delete it yourself.
See also
bool SetItem(wxListItem& info)
long SetItem(long index, int col, const wxString& label, int imageId = -1)
Sets information about the item.
wxListItem is a class with the following members:
long m_mask | Indicates which fields are valid. See the list of valid mask flags below. |
long m_itemId | The zero-based item position. |
int m_col | Zero-based column, if in report mode. |
long m_state | The state of the item. See the list of valid state flags below. |
long m_stateMask | A mask indicating which state flags are valid. See the list of valid state flags below. |
wxString m_text | The label/header text. |
int m_image | The zero-based index into an image list. |
long m_data | Application-defined data. |
int m_format | For columns only: the format. Can be wxLIST_FORMAT_LEFT, wxLIST_FORMAT_RIGHT or wxLIST_FORMAT_CENTRE. |
int m_width | For columns only: the column width. |
The m_mask member contains a bitlist specifying which of the other fields are valid. The flags are:
wxLIST_MASK_STATE | The m_state field is valid. |
wxLIST_MASK_TEXT | The m_text field is valid. |
wxLIST_MASK_IMAGE | The m_image field is valid. |
wxLIST_MASK_DATA | The m_data field is valid. |
wxLIST_MASK_WIDTH | The m_width field is valid. |
wxLIST_MASK_FORMAT | The m_format field is valid. |
The m_stateMask and m_state members take flags from the following:
wxLIST_STATE_DONTCARE | Don't care what the state is. Win32 only. |
wxLIST_STATE_DROPHILITED | The item is highlighted to receive a drop event. Win32 only. |
wxLIST_STATE_FOCUSED | The item has the focus. |
wxLIST_STATE_SELECTED | The item is selected. |
wxLIST_STATE_CUT | The item is in the cut state. Win32 only. |
The wxListItem object can also contain item-specific colour and font information: for this you need to call one of SetTextColour(), SetBackgroundColour() or SetFont() functions on it passing it the colour/font to use. If the colour/font is not specified, the default list control colour/font is used.
long SetItem(long index, int col, const wxString& label, int imageId = -1)
Sets a string field at a particular column.
wxPython note: In place of a single overloaded method name, wxPython implements the following methods:
SetItem(item) | Sets information about the given wxListItem. |
SetStringItem(index, col, label, imageId) | Sets a string or image at a given location. |
void SetItemBackgroundColour(long item, const wxColour& col)
Sets the background colour for this item. This function only works in report view.
The colour can be retrieved using GetItemBackgroundColour.
void SetItemCount(long count)
This method can only be used with virtual list controls. It is used to indicate to the control the number of items it contains. After calling it, the main program should be ready to handle calls to various item callbacks (such as OnGetItemText) for all items in the range from 0 to count.
bool SetItemData(long item, long data)
Associates application-defined data with this item.
void SetItemFont(long item, const wxFont& font)
Sets the item's font.
bool SetItemImage(long item, int image)
Sets the image associated with the item. The image is an index into the image list associated with the list control. In report view, this only sets the image for the first column.
bool SetItemImage(long item, int image, int selImage)
Sets the unselected and selected images associated with the item. The images are indices into the image list associated with the list control. This form is deprecated: selImage is not used.
bool SetItemImage(long item, long columnint image)
Sets the image associated with the item. In report view, you can specify the column. The image is an index into the image list associated with the list control.
bool SetItemPosition(long item, const wxPoint& pos)
Sets the position of the item, in icon or small icon view. Windows only.
bool SetItemState(long item, long state, long stateMask)
Sets the item state. For a list of state flags, see wxListCtrl::SetItem.
The stateMask indicates which state flags are valid.
void SetItemText(long item, const wxString& text)
Sets the item text for this item.
void SetItemTextColour(long item, const wxColour& col)
Sets the colour for this item. This function only works in report view.
The colour can be retrieved using GetItemTextColour.
void SetSingleStyle(long style, const bool add = true)
Adds or removes a single window style.
void SetTextColour(const wxColour& col)
Sets the text colour of the list control.
void SetWindowStyleFlag(long style)
Sets the whole window style, deleting all items.
bool SortItems(wxListCtrlCompare fnSortCallBack, long data)
Call this function to sort the items in the list control. Sorting is done using the specified fnSortCallBack function. This function must have the following prototype:
int wxCALLBACK wxListCompareFunction(long item1, long item2, long sortData)It is called each time when the two items must be compared and should return 0 if the items are equal, negative value if the first item is less than the second one and positive value if the first one is greater than the second one (the same convention as used by qsort(3)).
Parameters
item1
item2
data
Notice that the control may only be sorted on client data associated with the items, so you must use SetItemData if you want to be able to sort the items in the control.
Please see the listctrl sample for an example of using this function.
wxPython note: wxPython uses the sortData parameter to pass the Python function to call, so it is not available for programmer use. Call SortItems with a reference to a callable object that expects two parameters.
wxPerl note: In wxPerl the comparison function must take just two parameters; however, you may use a closure to achieve an effect similar to the SortItems third parameter.