/// <summary>
/// Initializes a new instance of the DropInfo class.
/// </summary>
///
/// <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>
public DropInfo(object sender, DragEventArgs e, DragInfo dragInfo)
{
var dataFormat = DragDrop.DataFormat.Name;
this.Data = (e.Data.GetDataPresent(dataFormat)) ? e.Data.GetData(dataFormat) : e.Data;
this.DragInfo = dragInfo;
this.KeyStates = e.KeyStates;
this.VisualTarget = sender as UIElement;
// if drop target isn't a ItemsControl
if (!(this.VisualTarget is ItemsControl))
{
// try to find next ItemsControl
var itemsControl = VisualTreeExtensions.GetVisualAncestor <ItemsControl>(this.VisualTarget);
if (itemsControl != null)
{
// now check if this ItemsControl is a drop target
if (DragDrop.GetIsDropTarget(itemsControl))
{
this.VisualTarget = itemsControl;
}
}
}
// visual target can be null, so give us a point...
this.DropPosition = this.VisualTarget != null?e.GetPosition(this.VisualTarget) : new Point();
if (this.VisualTarget is ItemsControl)
{
var itemsControl = (ItemsControl)this.VisualTarget;
var item = itemsControl.GetItemContainerAt(this.DropPosition);
var directlyOverItem = item != null;
this.TargetGroup = this.FindGroup(itemsControl, this.DropPosition);
this.VisualTargetOrientation = itemsControl.GetItemsPanelOrientation();
this.VisualTargetFlowDirection = itemsControl.GetItemsPanelFlowDirection();
if (item == null)
{
item = itemsControl.GetItemContainerAt(this.DropPosition, this.VisualTargetOrientation);
directlyOverItem = false;
}
if (item != null)
{
var itemParent = ItemsControl.ItemsControlFromItemContainer(item);
this.InsertIndex = itemParent.ItemContainerGenerator.IndexFromContainer(item);
this.TargetCollection = itemParent.ItemsSource ?? itemParent.Items;
if (directlyOverItem || typeof(TreeViewItem).IsAssignableFrom(item.GetType()))
{
this.TargetItem = itemParent.ItemContainerGenerator.ItemFromContainer(item);
this.VisualTargetItem = item;
}
var itemRenderSize = item.RenderSize;
if (this.VisualTargetOrientation == Orientation.Vertical)
{
var currentYPos = e.GetPosition(item).Y;
var targetHeight = itemRenderSize.Height;
if (currentYPos > targetHeight / 2)
{
this.InsertIndex++;
this.InsertPosition = RelativeInsertPosition.AfterTargetItem;
}
else
{
this.InsertPosition = RelativeInsertPosition.BeforeTargetItem;
}
if (currentYPos > targetHeight * 0.25 && currentYPos < targetHeight * 0.75)
{
this.InsertPosition |= RelativeInsertPosition.TargetItemCenter;
}
}
else
{
var currentXPos = e.GetPosition(item).X;
var targetWidth = itemRenderSize.Width;
if ((this.VisualTargetFlowDirection == FlowDirection.RightToLeft && currentXPos < targetWidth / 2) ||
(this.VisualTargetFlowDirection == FlowDirection.LeftToRight && currentXPos > targetWidth / 2))
{
this.InsertIndex++;
this.InsertPosition = RelativeInsertPosition.AfterTargetItem;
}
else
{
this.InsertPosition = RelativeInsertPosition.BeforeTargetItem;
}
if (currentXPos > targetWidth * 0.25 && currentXPos < targetWidth * 0.75)
{
this.InsertPosition |= RelativeInsertPosition.TargetItemCenter;
}
#if DEBUG
Console.WriteLine("==> DropInfo: {0}, {1}, {2}, X={3}", this.InsertPosition, item, this.InsertIndex, currentXPos);
#endif
}
}
else
{
this.TargetCollection = itemsControl.ItemsSource ?? itemsControl.Items;
this.InsertIndex = itemsControl.Items.Count;
}
}
}
