private void ExpandSingleProperties(PropertyViewItem item)
{
var node = GetNode(item);
// The data context of the item might be a "disconnected object"
if (node == null)
{
return;
}
var rule = GetRule(node);
if (node.Parent != null)
{
switch (rule)
{
case ExpandRule.Always:
// Always expand nodes that have this rule (without tracking them)
item.SetCurrentValue(ExpandableItemsControl.IsExpandedProperty, true);
break;
case ExpandRule.Never:
// Always collapse nodes that have this rule (without tracking them)
item.SetCurrentValue(ExpandableItemsControl.IsExpandedProperty, false);
break;
case ExpandRule.Once:
// Expand nodes that have this rule only if they have never been collapsed previously
var propertyPath = GetNode(item).DisplayPath;
if (!collapsedPropertyPaths.Contains(propertyPath))
{
item.SetCurrentValue(ExpandableItemsControl.IsExpandedProperty, true);
break;
}
goto default;
default:
// If the node is an only child, let's expand it
if (node.Parent.Children.Count == 1)
{
item.SetCurrentValue(ExpandableItemsControl.IsExpandedProperty, true);
// And keep a track of it, in case it has some siblings incoming
expandedItems.Add(item);
}
else
{
// If one of its siblings has been expanded because it was an only child at the time it was created, let's unexpand it.
// This will prevent to always have the first item expanded since the property items are generated as soon as a child is added.
expandedItems.Where(x => GetNode(x).Parent == node.Parent).ForEach(x => x.SetCurrentValue(ExpandableItemsControl.IsExpandedProperty, false));
}
break;
}
}
foreach (var container in item.Properties)
{
ExpandSingleProperties(container);
}
}