private void InsertRange(FlatNode parentNode, IEnumerable items, int itemIndex)
{
foreach (var item in items)
{
Insert(parentNode, item, itemIndex++);
}
}
/// <summary>
/// Gets the index of the node (where it must be inserted or removed).
/// </summary>
/// <param name="parentNode">The parent node.</param>
/// <param name="itemIndex">Index of the item.</param>
/// <returns></returns>
private static int GetNodeIndex(FlatNode parentNode, int itemIndex)
{
// node index is parent node + 1 (parent node itself) + previous siblings size
var nodeIndex = parentNode.Index + 1 + parentNode.GetChildOffset(itemIndex);
return(nodeIndex);
}
/// <summary>
/// Inserts the visual child.
/// And invalidates all impacted measures
/// </summary>
/// <param name="node">The node.</param>
/// <param name="index">The index.</param>
public void InsertVisualChild(FlatNode node, int index)
{
VisualChildren.Insert(index, node);
for (int i = index + 1; i < VisualChildren.Count; i++)
{
VisualChildren[i]._childOffset++;
}
AdjustAncestorsSize(+1);
}
private void CollapseNode(FlatNode itemNode)
{
if (!itemNode.IsExpanded)
{
return;
}
itemNode.IsExpanded = false;
Delete(itemNode);
}
private void ExpandNode(FlatNode itemNode)
{
if (itemNode.IsExpanded)
{
return;
}
itemNode.IsExpanded = true;
var itemChildren = itemNode.Parent == null ? _hierarchicalSource.Source : _hierarchicalSource.GetChildren(itemNode.Item);
SetChildrenSource(itemNode, itemChildren);
if (itemChildren != null)
{
InsertRange(itemNode, itemChildren, 0);
}
}
private void SetChildrenSource(FlatNode itemNode, IEnumerable itemChildren)
{
if (ReferenceEquals(itemNode.ChildrenSource, itemChildren))
{
return;
}
if (itemNode.ChildrenSource != null)
{
_nodesByChildren.Remove(itemNode.ChildrenSource);
}
itemNode.ChildrenSource.IfType <INotifyCollectionChanged>(c => c.CollectionChanged -= OnSourceCollectionChanged);
itemNode.ChildrenSource = itemChildren;
itemNode.ChildrenSource.IfType <INotifyCollectionChanged>(c => c.CollectionChanged += OnSourceCollectionChanged);
if (itemNode.ChildrenSource != null)
{
_nodesByChildren[itemNode.ChildrenSource] = itemNode;
}
}
/// <summary>
/// Initializes a new instance of the <see cref="FlatCollection" /> class.
/// </summary>
/// <param name="hierarchicalSource">The hierarchical source.</param>
/// <param name="target">The target.</param>
/// <exception cref="ArgumentNullException">
/// </exception>
/// <exception cref="ArgumentException">Must be empty</exception>
/// <exception cref="System.ArgumentNullException"></exception>
/// <exception cref="System.ArgumentException">Must be empty</exception>
public FlatCollection(IHierarchicalSource hierarchicalSource, IList target)
{
if (hierarchicalSource == null)
{
throw new ArgumentNullException(nameof(hierarchicalSource));
}
if (target == null)
{
throw new ArgumentNullException(nameof(target));
}
if (target.Count > 0)
{
throw new ArgumentException(@"Must be empty", nameof(target));
}
_hierarchicalSource = hierarchicalSource;
_target = target;
_rootNode = new FlatNode(null, null, true);
SetChildrenSource(_rootNode, _hierarchicalSource.Source);
InsertRange(_rootNode, _rootNode.ChildrenSource, 0);
}
private void Insert(FlatNode parentNode, object item, int itemIndex)
{
var insertIndex = GetNodeIndex(parentNode, itemIndex);
_target.Insert(insertIndex, _hierarchicalSource.GetContainerForItem(item));
var itemNode = new FlatNode(item, parentNode, _hierarchicalSource.IsExpanded(item));
parentNode.InsertVisualChild(itemNode, itemIndex);
_nodes[item] = itemNode;
if (itemNode.IsExpanded)
{
var itemChildren = _hierarchicalSource.GetChildren(item);
if (itemChildren != null)
{
SetChildrenSource(itemNode, itemChildren);
InsertRange(itemNode, itemChildren, 0);
}
}
}
private void OnSourceCollectionChanged(FlatNode itemNode, NotifyCollectionChangedEventArgs e)
{
// at any level, a parent may be collapsed, so we won't update anything at all here
for (var ancestor = itemNode; ancestor != null; ancestor = ancestor.Parent)
{
if (!ancestor.IsExpanded)
{
return;
}
}
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
InsertRange(itemNode, e.NewItems, e.NewStartingIndex);
break;
case NotifyCollectionChangedAction.Remove:
DeleteRange(e.OldItems);
break;
case NotifyCollectionChangedAction.Replace:
DeleteRange(e.OldItems);
InsertRange(itemNode, e.NewItems, e.NewStartingIndex);
break;
case NotifyCollectionChangedAction.Move:
// :confounded:
throw new NotImplementedException();
case NotifyCollectionChangedAction.Reset:
CollapseNode(itemNode);
ExpandNode(itemNode);
break;
default:
throw new ArgumentOutOfRangeException();
}
}
private void Delete(FlatNode node)
{
Delete(node.VisualChildren.ToArray());
SetChildrenSource(node, null);
}
/// <summary>
/// Initializes a new instance of the <see cref="FlatNode" /> class.
/// </summary>
/// <param name="item">The item.</param>
/// <param name="parent">The parent.</param>
/// <param name="isExpanded">if set to <c>true</c> [is expanded].</param>
public FlatNode(object item, FlatNode parent, bool isExpanded)
{
Item = item;
Parent = parent;
IsExpanded = isExpanded;
}