Wx::Perl::VirtualTreeCtrl - Build a tree control on demand
Wx::EvtHandler
Standard Wx::TreeCtrl and Wx::Window methods can be used with a virtual tree control.
use Wx::Perl::VirtualTreeCtrl 'EVT_POPULATE_TREE_ITEM';
my $tree = new Wx::Perl::VirtualTreeCtrl($tree_ctrl);
EVT_POPULATE_TREE_ITEM($self, $tree, \&AddChildren);
my $root = $tree->AddRoot($name, $data);
$tree->Expand($root);
sub AddChildren {
my ($self, $event) = @_;
my $tree = $event->GetEventObject;
my $item = $event->GetItem;
my $item_data = $tree->GetPlData($item);
if ($tree->GetChildrenCount($item, 0)) {
# update existing children ...
my ($child, $cookie) = $tree->GetFirstChild($item);
while ($child && $child->IsOk) {
my $child_data = $tree->GetPlData($child);
# synchronise deletions
if (child_was_deleted($child_data)) {
$tree->Delete($child);
}
($child, $cookie) = $tree->GetNextChild($child, $cookie);
}
} else {
# add children for the first time
my @child_data = expensive_process_to_get_children($item_data);
foreach (@child_data) {
my $child = $tree->AppendItem($item, $_->{name});
# make item expandable if it's a folder
$tree->SetItemHasChildren($child, 1) if ...;
}
}
}
This module implements a tree like the Wx::TreeCtrl except that it populates its items dynamically when nodes in the tree are expanded. You may prefer this control over the standard tree control when you are populating your tree from a remote source such as a database, or when your tree is very large.
This module implements the same interface as a standard Wx::TreeCtrl.
Returns a new Wx::Perl::VirtualTreeCtrl object. The parameters are the same as those required by a standard Wx::TreeCtrl.
Returns a Wx::Perl::VirtualTreeCtrl object that uses an existing Wx::TreeCtrl instead of creating its own. You may use this method when your interface is built using Wx::XRC resources or a third-party tool like wxGlade.
Returns a list of item labels from the root item down the provided path
Returns a Wx::TreeCtrl suitable for regular wxTreeEvents and Wx::Sizer operations
# Add a virtual tree to a sizer
$sizer->Add($vtree->GetTree, 1, wxALL|wxGROW, 4);
# Attach event listener for tree item activation (e.g. double click)
EVT_TREE_ITEM_ACTIVATED($win, $vtree->GetTree, \&onActivateItem);
The item is being expanded and the control is requesting that part of the tree be populated.
Your event callback will be passed the $event_handler and event object, as with other wxCommand events. The event object has the following accessors:
$event->GetEventObject() # returns the virtual tree control
$event->GetItem() # returns the tree item id that is being populated
See the example in "SYNOPSIS".
For further information, see the wxCommandEvent documentation, and the Event handling overview from the wxWidgets documentation.
Standard wxTreeEvents can be used with a virtual tree control. See "GetTree()" for examples.
The standard tree control from which this object is derived.
A tree control with checkboxes that is compatible with this module (you can have a virtual tree checker)
Simon Flack <cpan _at_ bbc _dot_ co _dot_ uk>
(c) BBC 2005. This program is free software; you can redistribute it and/or modify it under the GNU GPL.
See the file COPYING in this distribution, or http://www.gnu.org/licenses/gpl.txt
