public bool FilterAndAddChildren(IEnumerable <BaseDataItem> potentialChildren)
{
bool changed = false;
foreach (D item in potentialChildren.OfType <D>())
{
if (IsChild.Invoke(item))
{
var createdChild = CreateChildMethod.Invoke(item);
if (createdChild != null)
{
AddChildMethod.Invoke(createdChild);
changed = true;
}
}
}
return(changed);
}
public bool HandleChanges(DataChangedEvent e)
{
bool changed = false;
List <V> toRemove = new List <V>();
List <V> toReSort = new List <V>();
foreach (V child in Children)
{
// If it was deleted, then we mark it for remove
if (e.DeletedItems.Contains(child.Identifier))
{
toRemove.Add(child);
}
else
{
D edited = e.EditedItems.OfType <D>().FirstOrDefault(i => i.Identifier == child.Identifier);
// If it was edited
if (edited != null)
{
// If it's still a child, we'll need to re-sort it
if (IsChild.Invoke(edited))
{
toReSort.Add(child);
}
// Otherwise it's no longer a child, so remove it from this parent
else
{
toRemove.Add(child);
}
}
}
}
if (toRemove.Count > 0 || toReSort.Count > 0)
{
changed = true;
}
// Now remove all that need removing
foreach (V item in toRemove)
{
RemoveChildMethod.Invoke(item);
}
// And re-sort all that need re-sorting
foreach (V item in toReSort)
{
// First remove
RemoveChildMethod.Invoke(item);
// Then re-add
AddChildMethod.Invoke(item);
}
// And also add items that currently aren't children, but were edited and may be new children
if (FilterAndAddChildren(e.EditedItems.Where(i => !Children.Any(c => c.Identifier == i.Identifier))))
{
changed = true;
}
// And now add the new items
if (FilterAndAddChildren(e.NewItems))
{
changed = true;
}
return(changed);
}