void ShowPreview(SharpTreeViewItem item, DropPlace place)
{
previewNodeView = item.NodeView;
previewPlace = place;
if (place == DropPlace.Inside)
{
previewNodeView.TextBackground = SystemColors.HighlightBrush;
previewNodeView.Foreground = SystemColors.HighlightTextBrush;
}
else
{
if (insertMarker == null)
{
var adornerLayer = AdornerLayer.GetAdornerLayer(this);
var adorner = new GeneralAdorner(this);
insertMarker = new InsertMarker();
adorner.Child = insertMarker;
adornerLayer.Add(adorner);
}
insertMarker.Visibility = Visibility.Visible;
var p1 = previewNodeView.TransformToVisual(this).Transform(new Point());
var p = new Point(p1.X + previewNodeView.CalculateIndent() + 4.5, p1.Y - 3);
if (place == DropPlace.After)
{
p.Y += previewNodeView.ActualHeight;
}
insertMarker.Margin = new Thickness(p.X, p.Y, 0, 0);
SharpTreeNodeView secondNodeView = null;
var index = flattener.IndexOf(item.Node);
if (place == DropPlace.Before)
{
if (index > 0)
{
secondNodeView = (ItemContainerGenerator.ContainerFromIndex(index - 1) as SharpTreeViewItem).NodeView;
}
}
else if (index + 1 < flattener.Count)
{
secondNodeView = (ItemContainerGenerator.ContainerFromIndex(index + 1) as SharpTreeViewItem).NodeView;
}
var w = p1.X + previewNodeView.ActualWidth - p.X;
if (secondNodeView != null)
{
var p2 = secondNodeView.TransformToVisual(this).Transform(new Point());
w = Math.Max(w, p2.X + secondNodeView.ActualWidth - p.X);
}
insertMarker.Width = w + 10;
}
}
List <DropTarget> BuildDropTargets(SharpTreeViewItem item, DragEventArgs e)
{
var result = new List <DropTarget>();
var node = item.Node;
if (AllowDropOrder)
{
TryAddDropTarget(result, item, DropPlace.Before, e);
}
TryAddDropTarget(result, item, DropPlace.Inside, e);
if (AllowDropOrder)
{
if (node.IsExpanded && node.Children.Count > 0)
{
var firstChildItem = ItemContainerGenerator.ContainerFromItem(node.Children[0]) as SharpTreeViewItem;
TryAddDropTarget(result, firstChildItem, DropPlace.Before, e);
}
else
{
TryAddDropTarget(result, item, DropPlace.After, e);
}
}
var h = item.ActualHeight;
var y1 = 0.2 * h;
var y2 = h / 2;
var y3 = h - y1;
if (result.Count == 2)
{
if (result[0].Place == DropPlace.Inside &&
result[1].Place != DropPlace.Inside)
{
result[0].Y = y3;
}
else if (result[0].Place != DropPlace.Inside &&
result[1].Place == DropPlace.Inside)
{
result[0].Y = y1;
}
else
{
result[0].Y = y2;
}
}
else if (result.Count == 3)
{
result[0].Y = y1;
result[1].Y = y3;
}
if (result.Count > 0)
{
result[result.Count - 1].Y = h;
}
return(result);
}
internal void HandleDragOver(SharpTreeViewItem item, DragEventArgs e)
{
HidePreview();
var target = GetDropTarget(item, e);
if (target != null)
{
e.Handled = true;
ShowPreview(target.Item, target.Place);
}
}
protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
{
base.PrepareContainerForItemOverride(element, item);
SharpTreeViewItem container = element as SharpTreeViewItem;
container.ParentTreeView = this;
// Make sure that the line renderer takes into account the new bound data
if (container.NodeView != null)
{
container.NodeView.LinesRenderer.InvalidateVisual();
}
}
DropTarget GetDropTarget(SharpTreeViewItem item, DragEventArgs e)
{
var dropTargets = BuildDropTargets(item, e);
var y = e.GetPosition(item).Y;
foreach (var target in dropTargets)
{
if (target.Y >= y)
{
return(target);
}
}
return(null);
}
internal void HandleDrop(SharpTreeViewItem item, DragEventArgs e)
{
try {
HidePreview();
var target = GetDropTarget(item, e);
if (target != null)
{
e.Handled = true;
target.Node.InternalDrop(e, target.Index);
}
} catch (Exception ex) {
Debug.WriteLine(ex.ToString());
throw;
}
}
void TryAddDropTarget(List <DropTarget> targets, SharpTreeViewItem item, DropPlace place, DragEventArgs e)
{
SharpTreeNode node;
int index;
GetNodeAndIndex(item, place, out node, out index);
if (node != null)
{
e.Effects = DragDropEffects.None;
if (node.CanDrop(e, index))
{
DropTarget target = new DropTarget()
{
Item = item,
Place = place,
Node = node,
Index = index
};
targets.Add(target);
}
}
}
void TryAddDropTarget(List<DropTarget> targets, SharpTreeViewItem item, DropPlace place, DragEventArgs e)
{
SharpTreeNode node;
int index;
GetNodeAndIndex(item, place, out node, out index);
if (node != null) {
e.Effects = DragDropEffects.None;
if (node.CanDrop(e, index)) {
DropTarget target = new DropTarget() {
Item = item,
Place = place,
Node = node,
Index = index
};
targets.Add(target);
}
}
}
void ShowPreview(SharpTreeViewItem item, DropPlace place)
{
previewNodeView = item.NodeView;
previewPlace = place;
if (place == DropPlace.Inside) {
previewNodeView.TextBackground = SystemColors.HighlightBrush;
previewNodeView.Foreground = SystemColors.HighlightTextBrush;
}
else {
if (insertMarker == null) {
var adornerLayer = AdornerLayer.GetAdornerLayer(this);
var adorner = new GeneralAdorner(this);
insertMarker = new InsertMarker();
adorner.Child = insertMarker;
adornerLayer.Add(adorner);
}
insertMarker.Visibility = Visibility.Visible;
var p1 = previewNodeView.TransformToVisual(this).Transform(new Point());
var p = new Point(p1.X + previewNodeView.CalculateIndent() + 4.5, p1.Y - 3);
if (place == DropPlace.After) {
p.Y += previewNodeView.ActualHeight;
}
insertMarker.Margin = new Thickness(p.X, p.Y, 0, 0);
SharpTreeNodeView secondNodeView = null;
var index = flattener.IndexOf(item.Node);
if (place == DropPlace.Before) {
if (index > 0) {
secondNodeView = (ItemContainerGenerator.ContainerFromIndex(index - 1) as SharpTreeViewItem).NodeView;
}
}
else if (index + 1 < flattener.Count) {
secondNodeView = (ItemContainerGenerator.ContainerFromIndex(index + 1) as SharpTreeViewItem).NodeView;
}
var w = p1.X + previewNodeView.ActualWidth - p.X;
if (secondNodeView != null) {
var p2 = secondNodeView.TransformToVisual(this).Transform(new Point());
w = Math.Max(w, p2.X + secondNodeView.ActualWidth - p.X);
}
insertMarker.Width = w + 10;
}
}
void GetNodeAndIndex(SharpTreeViewItem item, DropPlace place, out SharpTreeNode node, out int index)
{
node = null;
index = 0;
if (place == DropPlace.Inside) {
node = item.Node;
index = node.Children.Count;
}
else if (place == DropPlace.Before) {
if (item.Node.Parent != null) {
node = item.Node.Parent;
index = node.Children.IndexOf(item.Node);
}
}
else {
if (item.Node.Parent != null) {
node = item.Node.Parent;
index = node.Children.IndexOf(item.Node) + 1;
}
}
}
DropTarget GetDropTarget(SharpTreeViewItem item, DragEventArgs e)
{
var dropTargets = BuildDropTargets(item, e);
var y = e.GetPosition(item).Y;
foreach (var target in dropTargets) {
if (target.Y >= y) {
return target;
}
}
return null;
}
List<DropTarget> BuildDropTargets(SharpTreeViewItem item, DragEventArgs e)
{
var result = new List<DropTarget>();
var node = item.Node;
if (AllowDropOrder) {
TryAddDropTarget(result, item, DropPlace.Before, e);
}
TryAddDropTarget(result, item, DropPlace.Inside, e);
if (AllowDropOrder) {
if (node.IsExpanded && node.Children.Count > 0) {
var firstChildItem = ItemContainerGenerator.ContainerFromItem(node.Children[0]) as SharpTreeViewItem;
TryAddDropTarget(result, firstChildItem, DropPlace.Before, e);
}
else {
TryAddDropTarget(result, item, DropPlace.After, e);
}
}
var h = item.ActualHeight;
var y1 = 0.2 * h;
var y2 = h / 2;
var y3 = h - y1;
if (result.Count == 2) {
if (result[0].Place == DropPlace.Inside &&
result[1].Place != DropPlace.Inside) {
result[0].Y = y3;
}
else if (result[0].Place != DropPlace.Inside &&
result[1].Place == DropPlace.Inside) {
result[0].Y = y1;
}
else {
result[0].Y = y2;
}
}
else if (result.Count == 3) {
result[0].Y = y1;
result[1].Y = y3;
}
if (result.Count > 0) {
result[result.Count - 1].Y = h;
}
return result;
}
internal void HandleDrop(SharpTreeViewItem item, DragEventArgs e)
{
try {
HidePreview();
var target = GetDropTarget(item, e);
if (target != null) {
e.Handled = true;
target.Node.InternalDrop(e, target.Index);
}
} catch (Exception ex) {
Debug.WriteLine(ex.ToString());
throw;
}
}
internal void HandleDragOver(SharpTreeViewItem item, DragEventArgs e)
{
HidePreview();
var target = GetDropTarget(item, e);
if (target != null) {
e.Handled = true;
ShowPreview(target.Item, target.Place);
}
}
internal void HandleDragLeave(SharpTreeViewItem item, DragEventArgs e)
{
HidePreview();
e.Handled = true;
}
internal void HandleDragEnter(SharpTreeViewItem item, DragEventArgs e)
{
HandleDragOver(item, e);
}
protected override void OnKeyDown(KeyEventArgs e)
{
SharpTreeViewItem container = e.OriginalSource as SharpTreeViewItem;
switch (e.Key)
{
case Key.Left:
if (container != null && ItemsControl.ItemsControlFromItemContainer(container) == this)
{
if (container.Node.IsExpanded)
{
container.Node.IsExpanded = false;
}
else if (container.Node.Parent != null)
{
this.FocusNode(container.Node.Parent);
}
e.Handled = true;
}
break;
case Key.Right:
if (container != null && ItemsControl.ItemsControlFromItemContainer(container) == this)
{
if (!container.Node.IsExpanded && container.Node.ShowExpander)
{
container.Node.IsExpanded = true;
}
else if (container.Node.Children.Count > 0)
{
// jump to first child:
container.MoveFocus(new TraversalRequest(FocusNavigationDirection.Down));
}
e.Handled = true;
}
break;
case Key.Return:
case Key.Space:
if (container != null && Keyboard.Modifiers == ModifierKeys.None && this.SelectedItems.Count == 1 && this.SelectedItem == container.Node)
{
container.Node.ActivateItem(e);
}
break;
case Key.Add:
if (container != null && ItemsControl.ItemsControlFromItemContainer(container) == this)
{
container.Node.IsExpanded = true;
e.Handled = true;
}
break;
case Key.Subtract:
if (container != null && ItemsControl.ItemsControlFromItemContainer(container) == this)
{
container.Node.IsExpanded = false;
e.Handled = true;
}
break;
case Key.Multiply:
if (container != null && ItemsControl.ItemsControlFromItemContainer(container) == this)
{
container.Node.IsExpanded = true;
ExpandRecursively(container.Node);
e.Handled = true;
}
break;
}
if (!e.Handled)
{
base.OnKeyDown(e);
}
}
internal void HandleDragEnter(SharpTreeViewItem item, DragEventArgs e)
{
HandleDragOver(item, e);
}
internal void HandleDragLeave(SharpTreeViewItem item, DragEventArgs e)
{
HidePreview();
e.Handled = true;
}