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%% Name:        vlbox.tex
%% Purpose:     wxVListBox documentation
%% Author:      Vadim Zeitlin
%% Modified by:
%% Created:     01.06.03
%% RCS-ID:      $Id$
%% Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwindows.org>
%% License:     wxWindows license
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\section{\class{wxVListBox}}\label{wxvlistbox}

wxVListBox is a listbox-like control with the following two main differences
from a regular listbox: it can have an arbitrarily huge number of items because
it doesn't store them itself but uses \helpref{OnDrawItem()}{wxvlistboxondrawitem} 
callback to draw them (so it is a {\Large V}irtual listbox) and its items can
have variable height as determined by 
\helpref{OnMeasureItem()}{wxvlistboxonmeasureitem} (so it is also a listbox
with the lines of {\Large V}ariable height).

Also, as a consequence of its virtual nature, it doesn't have any methods to
append or insert items in it as it isn't necessary to do it: you just have to
call \helpref{SetItemCount()}{wxvlistboxsetitemcount} to tell the control how
many items it should display. Of course, this also means that you will never
use this class directly because it has pure virtual functions, but will need to
derive your own class, such as \helpref{wxHtmlListBox}{wxhtmllistbox}, from it.

However it emits the same events as \helpref{wxListBox}{wxlistbox} and the same
event macros may be used with it.
 
\wxheading{Derived from}

\helpref{wxVScrolledWindow}{wxvscrolledwindow}

\wxheading{Include files}

<wx/vlbox.h>

\latexignore{\rtfignore{\wxheading{Members}}}


\membersection{wxVListBox::wxVListBox}\label{wxvlistboxctor}

\func{}{wxVListBox}{\param{wxWindow* }{parent}, \param{wxWindowID }{id = wxID\_ANY}, \param{const wxPoint\& }{pos = wxDefaultPosition}, \param{const wxSize\& }{size = wxDefaultSize}, \param{size\_t }{countItems = 0}, \param{long }{style = 0}, \param{const wxString\& }{name = wxVListBoxNameStr}}

Normal constructor which calls \helpref{Create()}{wxvlistboxcreate} internally.

\func{}{wxVListBox}{\void}

Default constructor, you must call \helpref{Create()}{wxvlistboxcreate} later.


\membersection{wxVListBox::Clear}\label{wxvlistboxclear}

\func{void}{Clear}{\void}

Deletes all items from the control.


\membersection{wxVListBox::Create}\label{wxvlistboxcreate}

\func{bool}{Create}{\param{wxWindow* }{parent}, \param{wxWindowID }{id = wxID\_ANY}, \param{const wxPoint\& }{pos = wxDefaultPosition}, \param{const wxSize\& }{size = wxDefaultSize}, \param{size\_t }{countItems = 0}, \param{long }{style = 0}, \param{const wxString\& }{name = wxVListBoxNameStr}}

Creates the control and optionally sets the initial number of items in it
(it may also be set or changed later with 
\helpref{SetItemCount()}{wxvlistboxsetitemcount}).

There are no special styles defined for wxVListBox, in particular the wxListBox
styles can not be used here.

Returns {\tt true} on success or {\tt false} if the control couldn't be created


\membersection{wxVListBox::GetItemCount}\label{wxvlistboxgetitemcount}

\constfunc{size\_t}{GetItemCount}{\void}

Get the number of items in the control.

\wxheading{See also}

\helpref{SetItemCount()}{wxvlistboxsetitemcount}


\membersection{wxVListBox::GetSelection}\label{wxvlistboxgetselection}

\constfunc{int}{GetSelection}{\void}

Get the currently selected item or $-1$ if there is no selection.


\membersection{wxVListBox::IsSelected}\label{wxvlistboxisselected}

\constfunc{bool}{IsSelected}{\param{size\_t }{line}}

Returns {\tt true} if this item is selected, {\tt false} otherwise.


\membersection{wxVListBox::OnDrawItem}\label{wxvlistboxondrawitem}

\constfunc{void}{OnDrawItem}{\param{wxDC\& }{dc}, \param{const wxRect\& }{rect}, \param{size\_t }{n}}

The derived class must implement this function to actually draw the item
with the given index on the provided DC.

\wxheading{Parameters}

\docparam{dc}{The device context to use for drawing}

\docparam{rect}{The bounding rectangle for the item being drawn (DC clipping
region is set to this rectangle before calling this function)}

\docparam{n}{The index of the item to be drawn}


\membersection{wxVListBox::OnDrawSeparator}\label{wxvlistboxondrawseparator}

\constfunc{void}{OnDrawSeparator}{\param{wxDC\& }{dc}, \param{wxRect\& }{rect}, \param{size\_t }{n}}

This method may be used to draw separators between the lines. The rectangle
passed to it may be modified, typically to deflate it a bit before passing to
\helpref{OnDrawItem()}{wxvlistboxondrawitem}.

The base class version of this method doesn't do anything.

\wxheading{Parameters}

\docparam{dc}{The device context to use for drawing}

\docparam{rect}{The bounding rectangle for the item}

\docparam{n}{The index of the item}


\membersection{wxVListBox::OnMeasureItem}\label{wxvlistboxonmeasureitem}

\constfunc{wxCoord}{OnMeasureItem}{\param{size\_t }{n}}

The derived class must implement this method to return the height of the
specified item (in pixels).


\membersection{wxVListBox::SetItemCount}\label{wxvlistboxsetitemcount}

\func{void}{SetItemCount}{\param{size\_t }{count}}

Set the number of items to be shown in the control.

This is just a synonym for
\helpref{wxVScrolledWindow::SetLineCount()}{wxvscrolledwindowsetlinecount}.


\membersection{wxVListBox::SetMargins}\label{wxvlistboxsetmargins}

\func{void}{SetMargins}{\param{const wxPoint\& }{pt}}

\func{void}{SetMargins}{\param{wxCoord }{x}, \param{wxCoord }{y}}

Set the margins: horizontal margin is the distance between the window
border and the item contents while vertical margin is half of the
distance between items.

By default both margins are $0$.


\membersection{wxVListBox::SetSelection}\label{wxvlistboxsetselection}

\func{void}{SetSelection}{\param{int }{selection}}

Set the selection to the specified item, if it is $-1$ the selection is
unset. The selected item will be automatically scrolled into view if it isn't
currently visible.