void DoTest(string tree1, string tree2, string expected)
{
var edits = TreeEdit.GetTreeEdits(new TestNode(tree1), new TestNode(tree2));
var actual = string.Join("; ", edits);
Assert.AreEqual(expected, actual);
}
void UpdateStructure(ITreeNode newRoot)
{
void Rebind(NSNodeItem item, ITreeNode newNode)
{
nodeToItem.Remove(item.Node);
item.Node = newNode;
nodeToItem[newNode] = item;
}
void DeleteDescendantsFromMap(NSNodeItem item)
{
item.Children.ForEach(c =>
{
Debug.Assert(nodeToItem.Remove(c.Node));
DeleteDescendantsFromMap(c);
});
}
var edits = TreeEdit.GetTreeEdits(rootItem.Node, newRoot);
Rebind(rootItem, newRoot);
foreach (var e in edits)
{
var node = nodeToItem[e.Node];
switch (e.Type)
{
case TreeEdit.EditType.Insert:
var insertedNode = CreateItem(e.NewChild);
node.Children.Insert(e.ChildIndex, insertedNode);
treeView.InsertItems(new NSIndexSet(e.ChildIndex), ToObject(node), NSTableViewAnimation.None);
break;
case TreeEdit.EditType.Delete:
var deletedNode = node.Children[e.ChildIndex];
node.Children.RemoveAt(e.ChildIndex);
Debug.Assert(deletedNode == nodeToItem[e.OldChild]);
nodeToItem.Remove(e.OldChild);
treeView.RemoveItems(new NSIndexSet(e.ChildIndex), ToObject(node), NSTableViewAnimation.None);
DeleteDescendantsFromMap(deletedNode);
break;
case TreeEdit.EditType.Reuse:
treeView.ReloadItem(ToObject(node));
Rebind(nodeToItem[e.OldChild], e.NewChild);
break;
case TreeEdit.EditType.Expand:
treeView.ExpandItem(ToObject(node), expandChildren: false);
break;
case TreeEdit.EditType.Collapse:
treeView.CollapseItem(ToObject(node), collapseChildren: false);
break;
}
}
}
void UpdateStructure(ITreeNode newRoot)
{
void Rebind(NSNodeItem item, ITreeNode newNode)
{
nodeToItem.Remove(item.Node);
item.Node = newNode;
nodeToItem[newNode] = item;
}
void DeleteDescendantsFromMap(NSNodeItem item)
{
item.Children.ForEach(c =>
{
Debug.Assert(nodeToItem.Remove(c.Node));
DeleteDescendantsFromMap(c);
});
}
var edits = TreeEdit.GetTreeEdits(rootItem.Node, newRoot, new TreeEdit.Options
{
TemporariltyExpandParentToInitChildren = true
});
Rebind(rootItem, newRoot);
foreach (var e in edits)
{
var node = nodeToItem[e.Node];
switch (e.Type)
{
case TreeEdit.EditType.Insert:
var insertedNode = CreateItem(e.NewChild);
node.Children.Insert(e.ChildIndex, insertedNode);
using (var set = new NSIndexSet(e.ChildIndex))
treeView.InsertItems(set, ToObject(node), NSTableViewAnimation.None);
break;
case TreeEdit.EditType.Delete:
var deletedNode = node.Children[e.ChildIndex];
node.Children.RemoveAt(e.ChildIndex);
Debug.Assert(deletedNode == nodeToItem[e.OldChild]);
nodeToItem.Remove(e.OldChild);
using (var set = new NSIndexSet(e.ChildIndex))
treeView.RemoveItems(set, ToObject(node), NSTableViewAnimation.None);
DeleteDescendantsFromMap(deletedNode);
break;
case TreeEdit.EditType.Reuse:
var viewItem = nodeToItem [e.OldChild];
Rebind(viewItem, e.NewChild);
treeView.ReloadItem(ToObject(viewItem), reloadChildren: false);
if (owner.OnUpdateRowView != null)
{
var rowIdx = treeView.RowForItem(ToObject(viewItem));
var rowView = rowIdx >= 0 ? treeView.GetRowView(rowIdx, makeIfNecessary: false) : null;
if (rowView != null)
{
owner.OnUpdateRowView(rowView, (Node)e.NewChild);
}
}
break;
case TreeEdit.EditType.Expand:
treeView.ExpandItem(ToObject(node), expandChildren: false);
break;
case TreeEdit.EditType.Collapse:
treeView.CollapseItem(ToObject(node), collapseChildren: false);
break;
}
}
}
public void Update(Node newRoot)
{
var finalizeActions = new List <Action>();
bool updateBegun = false;
Action beginUpdate = () =>
{
if (!updateBegun)
{
// Call ListView's BeginUpdate/EndUpdate only when needed
// tree structure changed to avoid flickering when only selection changes.
treeView.BeginUpdate();
updateBegun = true;
}
};
updating = true;
try
{
var edits = TreeEdit.GetTreeEdits(currentRoot, newRoot);
currentRoot = newRoot;
foreach (var e in edits)
{
TreeNode node = e.Node == newRoot ? null : nodeToViewNodes[e.Node];
TreeNodeCollection nodeChildren = e.Node == newRoot ? treeView.Nodes : node.Nodes;
switch (e.Type)
{
case TreeEdit.EditType.Insert:
beginUpdate();
var insertedNode = CreateViewNode((Node)e.NewChild);
nodeChildren.Insert(e.ChildIndex, insertedNode);
break;
case TreeEdit.EditType.Delete:
beginUpdate();
var deletedNode = nodeChildren[e.ChildIndex];
nodeChildren.RemoveAt(e.ChildIndex);
Debug.Assert(deletedNode == nodeToViewNodes[e.OldChild]);
nodeToViewNodes.Remove(e.OldChild);
DeleteDescendantsFromMap(deletedNode);
break;
case TreeEdit.EditType.Reuse:
var nodeToReuse = nodeToViewNodes[e.OldChild];
Rebind(nodeToReuse, (Node)e.NewChild);
UpdateViewNode(nodeToReuse, (Node)e.NewChild, (Node)e.OldChild, beginUpdate);
break;
case TreeEdit.EditType.Expand:
finalizeActions.Add(node.Expand);
break;
case TreeEdit.EditType.Collapse:
finalizeActions.Add(() => node.Collapse(ignoreChildren: true));
break;
case TreeEdit.EditType.Select:
treeView.SelectNode(node);
break;
case TreeEdit.EditType.Deselect:
treeView.DeselectNode(node);
break;
}
}
}
finally
{
if (updateBegun)
{
treeView.EndUpdate();
}
finalizeActions.ForEach(a => a());
if (treeView.SelectedNode is ViewNode selected && !selected.Node.IsSelected)
{
// When no nodes are explicitly selected, the OS selects one for us,
// and we have to undo that.
// Another scenario is that a node that was optimistically allowed to be selected in BeforeSelect
// turned out not be selected.
treeView.SelectedNode = null;
}
updating = false;
}
}
