/// <summary>
/// This method is raised when Children.Comparer is chamged
/// </summary>
/// <param name="sender">The collection in which the comparer was changed</param>
protected void OnChildListComparerChanged(ObservableSortedCollection <ObservableSortedTree <T> > sender,
IComparer <ObservableSortedTree <T> > oldComparer)
{
//this.Comparer = sender.Comparer;
OnPropertyChanged(nameof(Comparer));
OnComparerChanged(oldComparer);
}
protected ObservableSortedTree(T value, IComparer <ObservableSortedTree <T> > comparer, ObservableSortedCollection <ObservableSortedTree <T> > children)
{
Value = value;
Children = children;
Comparer = comparer;
Root = this;
}
/// <summary>
/// attaches and detaches events for the child list when it is changed. Triggered by setting this.Children
/// </summary>
/// <param name="oldChildren">the old child tree list</param>
/// <param name="newChildren">the new child tree list</param>
private void manageChildListEvents(ObservableSortedCollection <ObservableSortedTree <T> > oldChildren,
ObservableSortedCollection <ObservableSortedTree <T> > newChildren)
{
if (oldChildren != null)
{
oldChildren.ItemAdded -= OnChildTreeAdded;
oldChildren.ItemRemoved -= OnChildTreeRemoved;
oldChildren.ItemChanged -= OnChildTreeChanged;
oldChildren.ComparerChanged -= OnChildListComparerChanged;
foreach (var child in oldChildren)
{
OnDetachChild(child);
}
}
//_children = newChildren;
if (newChildren != null)
{
newChildren.ItemAdded += OnChildTreeAdded;
newChildren.ItemRemoved += OnChildTreeRemoved;
newChildren.ItemChanged += OnChildTreeChanged;
newChildren.ComparerChanged += OnChildListComparerChanged;
foreach (var child in newChildren)
{
OnAttachChild(child);
}
}
}
} = true; //use this bool to allow constructor set child list and child factory (whhich call setChildren)
protected override void setChildren(ObservableSortedCollection <ObservableSortedTree <T> > newChildren)
{
if (initialising)
{
base.setChildren(newChildren);
}
else
{
throw new NotImplementedException("Cannot manually set the children list in a lazy tree");
}
}
/// <summary>
/// Overrideable method for setting the collection of current child tree elements
/// Note: Parent, and hence Root, automatically updated for all new children
///
/// </summary>
/// <param name="newChildren">the list of child tree elements</param>
protected virtual void setChildren(ObservableSortedCollection <ObservableSortedTree <T> > newChildren)
{
if (ReferenceEquals(newChildren, _children))
{
return;
}
var old = _children;
_children = newChildren;
// _children.Comparer = this.Comparer;
manageChildListEvents(old, _children);
OnChildListChanged(old);
OnPropertyChanged(nameof(Children));
//OnPropertyChanged(nameof(HasChildren));
}
protected virtual void OnChildListChanged(ObservableSortedCollection <ObservableSortedTree <T> > oldChildren)
{
/*if (this._children != null)
* this._children.Comparer = this.Comparer;*/
ChildListChanged?.Invoke(this, oldChildren);
bool oldHasChild = oldChildren != null && oldChildren.Count > 0;
bool newHasChild = this._children != null && this._children.Count > 0;
if (oldChildren != null && this.Children != null)
{
this.Children.Comparer = oldChildren.Comparer;
}
if (oldHasChild != newHasChild)
{
OnPropertyChanged(nameof(HasChildren));
}
}
public void GenerateChildren()
{
//regenerating children bool is to allow child factory to be called when it has been changed
//if AreChildrenGenerated is true when the child factory is changed, this function would return immediately, and the old children would remain
//this allows the old chilren to be destroyed and new children created when needed
if (AreChildrenGenerated && !regeneratingChildren)
{
return;
}
regeneratingChildren = false;
AreChildrenGenerated = true;
var childCollection = new ObservableSortedCollection <ObservableSortedTree <T> >(_inheritComparer);
_inheritComparer = null;
base.setChildren(childCollection);
//AreChildrenGenerated must be set to true before base.GetChildren, otherwise it will think the children have not yet been generated and start generating them again
base.getChildren().AddRange(InternalChildFactory(this));
onChildrenGenerated();
}
