/// <summary>
/// Initializes a new instance of the DropInfo class.
/// <param name="sender">The sender of the drag event.</param>
/// <param name="e">The drag event.</param>
/// <param name="dragInfo">Information about the source of the drag, if the drag came from within the framework.</param>
/// <param name="eventType">The type of the underlying event (tunneled or bubbled).</param>
/// </summary>
public DropInfo(object sender, DragEventArgs e, [CanBeNull] DragInfo dragInfo, EventType eventType)
{
DragInfo = dragInfo;
KeyStates = e.KeyStates;
EventType = eventType;
var dataFormat = dragInfo?.DataFormat;
Data = dataFormat != null && e.Data.GetDataPresent(dataFormat.Name) ? e.Data.GetData(dataFormat.Name) : e.Data;
VisualTarget = sender as UIElement;
// if there is no drop target, find another
if (!VisualTarget.IsDropTarget())
{
// try to find next element
var element = VisualTarget.TryGetNextAncestorDropTargetElement();
if (element != null)
{
VisualTarget = element;
}
}
// try find ScrollViewer
var dropTargetScrollViewer = DragDrop.GetDropTargetScrollViewer(VisualTarget);
if (dropTargetScrollViewer != null)
{
TargetScrollViewer = dropTargetScrollViewer;
}
else if (VisualTarget is TabControl)
{
var tabPanel = VisualTarget.FindVisualChild <TabPanel>();
TargetScrollViewer = tabPanel?.FindVisualParent <ScrollViewer>();
}
else
{
TargetScrollViewer = VisualTarget?.FindVisualChild <ScrollViewer>();
}
TargetScrollingMode = VisualTarget != null?DragDrop.GetDropScrollingMode(VisualTarget) : ScrollingMode.Both;
// visual target can be null, so give us a point...
DropPosition = VisualTarget != null?e.GetPosition(VisualTarget) : new Point();
if (VisualTarget is TabControl)
{
if (!HitTestUtilities.HitTest4Type <TabPanel>(VisualTarget, DropPosition))
{
return;
}
}
if (VisualTarget is ItemsControl itemsControl)
{
//System.Diagnostics.Debug.WriteLine(">>> Name = {0}", itemsControl.Name);
// get item under the mouse
item = itemsControl.GetItemContainerAt(DropPosition);
var directlyOverItem = item != null;
TargetGroup = itemsControl.FindGroup(DropPosition);
VisualTargetOrientation = itemsControl.GetItemsPanelOrientation();
VisualTargetFlowDirection = itemsControl.GetItemsPanelFlowDirection();
if (item == null)
{
// ok, no item found, so maybe we can found an item at top, left, right or bottom
item = itemsControl.GetItemContainerAt(DropPosition, VisualTargetOrientation);
directlyOverItem = DropPosition.DirectlyOverElement(item, itemsControl);
}
if (item == null && TargetGroup != null && TargetGroup.IsBottomLevel)
{
var itemData = TargetGroup.Items.FirstOrDefault();
if (itemData != null)
{
item = itemsControl.ItemContainerGenerator.ContainerFromItem(itemData) as UIElement;
directlyOverItem = DropPosition.DirectlyOverElement(item, itemsControl);
}
}
if (item != null)
{
itemParent = ItemsControl.ItemsControlFromItemContainer(item);
VisualTargetOrientation = itemParent.GetItemsPanelOrientation();
VisualTargetFlowDirection = itemParent.GetItemsPanelFlowDirection();
InsertIndex = itemParent.ItemContainerGenerator.IndexFromContainer(item);
TargetCollection = itemParent.ItemsSource ?? itemParent.Items;
var tvItem = item as TreeViewItem;
if (directlyOverItem || tvItem != null)
{
VisualTargetItem = item;
TargetItem = itemParent.ItemContainerGenerator.ItemFromContainer(item);
}
var expandedTVItem = tvItem != null && tvItem.HasHeader && tvItem.HasItems && tvItem.IsExpanded;
var itemRenderSize = expandedTVItem ? tvItem.GetHeaderSize() : item.RenderSize;
if (VisualTargetOrientation == Orientation.Vertical)
{
// Get the current position relative to the items container
var currentYPos = e.GetPosition(item).Y;
// Get items container height
var targetHeight = itemRenderSize.Height;
var topGap = targetHeight * 0.25;
var bottomGap = targetHeight * 0.75;
if (currentYPos > targetHeight / 2)
{
// If items control is tree viewer
if (expandedTVItem && (currentYPos < topGap || currentYPos > bottomGap))
{
VisualTargetItem = tvItem.ItemContainerGenerator.ContainerFromIndex(0) as UIElement;
TargetItem = VisualTargetItem != null?tvItem.ItemContainerGenerator.ItemFromContainer(VisualTargetItem) : null;
TargetCollection = tvItem.ItemsSource ?? tvItem.Items;
InsertIndex = 0;
InsertPosition = RelativeInsertPosition.BeforeTargetItem;
}
else
{
InsertIndex++;
InsertPosition = RelativeInsertPosition.AfterTargetItem;
}
}
else
{
InsertPosition = RelativeInsertPosition.BeforeTargetItem;
}
if (currentYPos > topGap && currentYPos < bottomGap)
{
if (tvItem != null)
{
TargetCollection = tvItem.ItemsSource ?? tvItem.Items;
InsertIndex = TargetCollection != null?TargetCollection.OfType <object>().Count() : 0;
}
InsertPosition |= RelativeInsertPosition.TargetItemCenter;
}
//System.Diagnostics.Debug.WriteLine("==> DropInfo: pos={0}, idx={1}, Y={2}, Item={3}", InsertPosition, InsertIndex, currentYPos, item);
}
else
{
var currentXPos = e.GetPosition(item).X;
var targetWidth = itemRenderSize.Width;
if (VisualTargetFlowDirection == FlowDirection.RightToLeft)
{
if (currentXPos > targetWidth / 2)
{
InsertPosition = RelativeInsertPosition.BeforeTargetItem;
}
else
{
InsertIndex++;
InsertPosition = RelativeInsertPosition.AfterTargetItem;
}
}
else if (VisualTargetFlowDirection == FlowDirection.LeftToRight)
{
if (currentXPos > targetWidth / 2)
{
InsertIndex++;
InsertPosition = RelativeInsertPosition.AfterTargetItem;
}
else
{
InsertPosition = RelativeInsertPosition.BeforeTargetItem;
}
}
if (currentXPos > targetWidth * 0.25 && currentXPos < targetWidth * 0.75)
{
if (tvItem != null)
{
TargetCollection = tvItem.ItemsSource ?? tvItem.Items;
InsertIndex = TargetCollection != null?TargetCollection.OfType <object>().Count() : 0;
}
InsertPosition |= RelativeInsertPosition.TargetItemCenter;
}
//System.Diagnostics.Debug.WriteLine("==> DropInfo: pos={0}, idx={1}, X={2}, Item={3}", InsertPosition, InsertIndex, currentXPos, item);
}
}
else
{
TargetCollection = itemsControl.ItemsSource ?? itemsControl.Items;
InsertIndex = itemsControl.Items.Count;
//System.Diagnostics.Debug.WriteLine("==> DropInfo: pos={0}, item=NULL, idx={1}", InsertPosition, InsertIndex);
}
}
else
{
VisualTargetItem = VisualTarget;
}
}
