private void AddToSelection([NotNull] EntityHierarchyElementViewModel element)
{
lock (LockObject)
{
if (!element.IsSelectable)
{
return;
}
// Add the entity id to the selected ids
SelectedIds.Add(element.Id);
// Check if one of its parents is in the selection
var parent = element.TransformParent;
while (parent != null)
{
if (SelectedIds.Contains(parent.Id))
{
break;
}
parent = parent.TransformParent;
}
// If so, the SelectedRootIds collection does not need to be updated.
if (parent != null)
{
return;
}
// Otherwise, it's a new root entity in the selection.
SelectedRootIds.Add(element.Id);
// Remove its children that were previously root entities in the selection.
foreach (var child in element.TransformChildren.SelectDeep(x => x.TransformChildren))
{
SelectedRootIds.Remove(child.Id);
}
}
}
private void RemoveFromSelection([NotNull] EntityHierarchyElementViewModel element)
{
lock (LockObject)
{
SelectedIds.Remove(element.Id);
// Remove the root entity from the selected root entities
if (SelectedRootIds.Remove(element.Id) && element.IsLoaded)
{
// Ensure all children that are selected are properly added to the selected root collection
foreach (var child in element.TransformChildren.SelectDeep(x => x.TransformChildren).Where(x => SelectedIds.Contains(x.Id)))
{
// Check if one of its parents is in the selection
var parent = child.TransformParent;
while (parent != element && parent != null)
{
if (SelectedIds.Contains(parent.Id))
{
break;
}
parent = parent.TransformParent;
}
// If so, the SelectedRootIds collection does not need to be updated.
if (parent != element)
{
return;
}
// Otherwise, it's a new root entity in the selection.
SelectedRootIds.Add(child.Id);
}
}
}
}