void SetElementExpanded(ILiveElement element, bool expand)
{
var expandState = _expandMap.GetOrCreateValue(element);
expandState.IsExpanded = expand;
_expandToggled.OnNext(Unit.Default);
}
public static IEnumerable <ILiveElement> DescendantsAndSelf(this ILiveElement element)
{
yield return(element);
foreach (var descendant in element.Children.Value.SelectMany(DescendantsAndSelf))
{
yield return(descendant);
}
}
bool GetElementExpanded(ILiveElement element, bool fallback)
{
ElementExpandState expandState;
if (_expandMap.TryGetValue(element, out expandState))
{
return(expandState.IsExpanded);
}
return(fallback);
}
public void Update(
ILiveElement element,
int depth,
int rowOffset,
int expandedDescendantCount,
bool expandToggleEnabled,
bool isExpanded,
bool isSelected,
bool isAncestorSelected,
bool isDescendantSelected)
{
_element.OnNextDistinct(Optional.Some(element));
_rowOffset.OnNextDistinct(rowOffset);
_expandedDescendantCount.OnNextDistinct(expandedDescendantCount);
_depth.OnNextDistinct(depth);
_isExpanded.OnNextDistinct(isExpanded);
_expandToggleEnabled.OnNextDistinct(expandToggleEnabled);
_isSelected.OnNextDistinct(isSelected);
_isAncestorSelected.OnNextDistinct(isAncestorSelected);
_isDescendantSelected = isDescendantSelected;
}
static ILiveElement[] GetSelectionPath(ILiveElement root, Optional <ILiveElement> selectedElement)
{
if (!selectedElement.HasValue)
{
return new ILiveElement[] { }
}
;
// First we count depth and see if selection is descendant of our root
var selected = selectedElement.Value;
var current = selected;
int depth = 0;
while (current != root)
{
var liveParent = current.Parent as ILiveElement;
if (liveParent == null)
{
return(new ILiveElement[] { });
}
depth++;
current = liveParent;
}
// Then we walk down again and build the selection array
var selectionPath = new ILiveElement[depth + 1];
current = selected;
do
{
selectionPath[depth] = current;
current = current.Parent as ILiveElement;
} while (depth-- > 0);
return(selectionPath);
}
}
State ScanElementTree(
ILiveElement root,
int visibleRowCount,
int visibleRowOffset,
Optional <ILiveElement> selectedElement,
Optional <ILiveElement> previewElement)
{
// Update visible rows ake sure we have enough
var updates = new Dictionary <ILiveElement, Action <RowModel> >();
var allExpandedElements = new List <ILiveElement>(_allExpandedElements.Count * 2);
var selectedElementRowOffset = Optional.None <int>();
var previewElementRowOffset = Optional.None <int>();
ScanElementTree(
treeModel: this._tree,
element: root,
updates: updates,
allExpandedElements: allExpandedElements,
visibleRowCount: visibleRowCount,
visibleRowOffset: visibleRowOffset,
depth: 0,
selectionPath: GetSelectionPath(root, selectedElement),
previewElement: previewElement,
isAncestorSelected: false,
selectedElementRowOffset: ref selectedElementRowOffset,
previewElementRowOffset: ref previewElementRowOffset);
return(new State(
_tree,
VisibleRows,
allExpandedElements.Count,
visibleRows => UpdateRows(visibleRows, updates),
selectedElementRowOffset,
visibleRowOffset,
visibleRowCount,
allExpandedElements));
}
Optional <Action> GetDropAction(ILiveElement thisElement, DropPosition position, object dragged)
{
var draggedElement = dragged as ILiveElement;
var sourceFragment = dragged as SourceFragment;
var bytes = dragged as byte[];
Func <SourceFragment> cut;
if (draggedElement != null)
{
var node = thisElement;
while (node != null)
{
if (node.Equals(draggedElement))
{
return(Optional.None());
}
node = node.Parent as ILiveElement;
}
cut = () => draggedElement.Cut().Result;
}
else if (bytes != null)
{
cut = () => SourceFragment.FromBytes(bytes);
}
else if (sourceFragment != null)
{
cut = () => sourceFragment;
}
else
{
return(Optional.None());
}
switch (position)
{
case DropPosition.Inside:
if (!_isExpanded.Value)
{
return((Action)(
() =>
{
var src = cut();
var element = thisElement.Paste(src);
_tree._context.Select(element);
}));
}
break;
case DropPosition.After:
case DropPosition.Before:
if (_depth.Value > 0)
{
return((Action)(() =>
{
var src = cut();
var element = position == DropPosition.Before ? thisElement.PasteBefore(src) : thisElement.PasteAfter(src);
_tree._context.Select(element);
}));
}
break;
}
return(Optional.None());
}
static bool CanExpand(ILiveElement element, int depth)
{
return(element.Children.Value.Any() && (depth == 0 || !element.UxClass().Value.HasValue));
}
/// <summary>
/// Walks through all expanded elements of tree, adding actions to updates for pending row updates.
/// Returns index of selected element
/// </summary>
static void ScanElementTree(
TreeViewModel treeModel,
ILiveElement element,
Dictionary <ILiveElement, Action <RowModel> > updates,
List <ILiveElement> allExpandedElements,
int visibleRowCount,
int visibleRowOffset,
int depth,
ILiveElement[] selectionPath,
Optional <ILiveElement> previewElement,
bool isAncestorSelected,
ref Optional <int> selectedElementRowOffset,
ref Optional <int> previewElementRowOffset)
{
var rowOffset = allExpandedElements.Count;
allExpandedElements.Add(element);
// A node with children can expand, unless it has a "ux:Class" attribute
var canExpand = CanExpand(element, depth);
// We expand up to 2 levels by default
var expandByDefault = depth < 2;
// Check if this element is an ancestor of selection
var isDescendantSelected = depth < (selectionPath.Length - 1) && selectionPath[depth].Equals(element);
// This is the selected element when we're at the end of the selection path
var isSelected = depth == (selectionPath.Length - 1) && selectionPath[depth].Equals(element);
var isExpanded = canExpand && (isDescendantSelected || treeModel.GetElementExpanded(element, expandByDefault));
if (previewElement.Select(pe => pe == element).Or(false))
{
previewElementRowOffset = rowOffset;
}
if (isSelected)
{
selectedElementRowOffset = rowOffset;
}
var children = element.Children.Value;
if (isExpanded)
{
foreach (var child in children)
{
ScanElementTree(
treeModel: treeModel,
element: child,
updates: updates,
allExpandedElements: allExpandedElements,
visibleRowCount: visibleRowCount,
visibleRowOffset: visibleRowOffset,
depth: depth + 1,
selectionPath: selectionPath,
previewElement: previewElement,
isAncestorSelected: isSelected | isAncestorSelected,
selectedElementRowOffset: ref selectedElementRowOffset,
previewElementRowOffset: ref previewElementRowOffset);
}
}
var lastDescendantRowOffset = allExpandedElements.Count - 1;
if ((rowOffset >= visibleRowOffset && rowOffset < visibleRowOffset + visibleRowCount) ||
(rowOffset < visibleRowOffset && lastDescendantRowOffset >= visibleRowOffset))
{
updates[element] = rowModel => rowModel.Update(
element: element,
depth: depth,
rowOffset: rowOffset,
expandedDescendantCount: lastDescendantRowOffset - rowOffset,
expandToggleEnabled: depth > 0 && canExpand, // Don't allow collapse of root
isExpanded: isExpanded,
isSelected: isSelected,
isAncestorSelected: isAncestorSelected,
isDescendantSelected: isDescendantSelected);
}
}
public static IBehaviorProperty <Optional <string> > UxClass(this ILiveElement element)
{
return(element["ux:Class"]);
}
