/// <summary>
/// First determine whether the drag data is supported.
/// Finally handle the actual drop when <code>bDrop</code> is true.
/// Insert the item before the drop target. When there is no drop
/// target (dropped on empty space), add to the end of the items.
///
/// Note that only TreeViewItems with no children can be moved.
/// </summary>
/// <param name="bDrop">True to perform an actual drop, otherwise just return e.Effects</param>
/// <param name="sender">DragDrop event <code>sender</code></param>
/// <param name="e">DragDrop event arguments</param>
private void DragOverOrDrop(bool bDrop, object sender, DragEventArgs e)
{
TreeViewDataProvider <TSourceContainer, TSourceObject> dataProvider = this.GetData(e) as TreeViewDataProvider <TSourceContainer, TSourceObject>;
if (dataProvider != null)
{
TSourceObject dragSourceObject = dataProvider.SourceObject as TSourceObject;
TSourceContainer dragSourceContainer = dataProvider.SourceContainer as TSourceContainer;
Debug.Assert(dragSourceObject != null);
Debug.Assert(dragSourceContainer != null);
ListBox dropContainer = Utilities.FindParentControlIncludingMe <ListBox>(e.Source as DependencyObject);
ListBoxItem dropTarget = Utilities.FindParentControlIncludingMe <ListBoxItem>(e.Source as DependencyObject);
if (!dragSourceObject.HasItems) // TreeViewItem must be a leaf
{
if (bDrop)
{
dataProvider.Unparent();
ListBoxItem item = new ListBoxItem();
item.Content = dragSourceObject.Header;
item.ToolTip = dragSourceObject.ToolTip;
if (dropTarget == null)
{
dropContainer.Items.Add(item);
}
else
{
dropContainer.Items.Insert(dropContainer.Items.IndexOf(dropTarget), item);
}
item.IsSelected = true;
item.BringIntoView();
}
e.Effects = DragDropEffects.Move;
e.Handled = true;
}
else
{
e.Effects = DragDropEffects.None;
e.Handled = true;
}
}
}
/// <summary>
/// First determine whether the drag data is supported.
/// Finally handle the actual drop when <code>bDrop</code> is true.
/// Add the item as the drop target's child when Shift is not pressed,
/// or insert the item before the drop target when Shift is pressed.
/// When there is no drop target (dropped on empty space),
/// add to the end of the items.
///
/// Note that the source object cannot be an ancestor of the drop target.
/// </summary>
/// <param name="bDrop">True to perform an actual drop, otherwise just return e.Effects</param>
/// <param name="sender">DragDrop event <code>sender</code></param>
/// <param name="e">DragDrop event arguments</param>
private void DragOverOrDrop(bool bDrop, object sender, DragEventArgs e)
{
TreeViewDataProvider <TContainer, TObject> dataProvider = this.GetData(e) as TreeViewDataProvider <TContainer, TObject>;
if (dataProvider != null)
{
TContainer dragSourceContainer = dataProvider.SourceContainer as TContainer;
TreeViewItem dragSourceObject = dataProvider.SourceObject as TreeViewItem;
Debug.Assert(dragSourceContainer != null);
Debug.Assert(dragSourceObject != null);
TContainer dropContainer = Utilities.FindParentControlIncludingMe <TContainer>(sender as DependencyObject);
Debug.Assert(dropContainer != null);
TObject dropTarget = e.Source as TObject;
if (dropTarget == null)
{
if (bDrop)
{
dataProvider.Unparent();
dropContainer.Items.Add(dragSourceObject);
}
e.Effects = DragDropEffects.Move;
e.Handled = true;
#if PRINT2OUTPUT
Debug.WriteLine(" Move0");
#endif
}
else
{
bool IsAncestor = dragSourceObject.IsAncestorOf(dropTarget);
if ((dataProvider.KeyStates & DragDropKeyStates.ShiftKey) != 0)
{
ItemsControl shiftDropTarget = Utilities.FindParentControlExcludingMe <ItemsControl>(dropTarget);
Debug.Assert(shiftDropTarget != null);
if (!IsAncestor)
{
if (bDrop)
{
dataProvider.Unparent();
Debug.Assert(shiftDropTarget != null);
shiftDropTarget.Items.Insert(shiftDropTarget.Items.IndexOf(dropTarget), dragSourceObject);
}
e.Effects = DragDropEffects.Link;
e.Handled = true;
#if PRINT2OUTPUT
Debug.WriteLine(" Link1");
#endif
}
else
{
e.Effects = DragDropEffects.None;
e.Handled = true;
#if PRINT2OUTPUT
Debug.WriteLine(" None1");
#endif
}
}
else
{
if (!IsAncestor && (dragSourceObject != dropTarget))
{
if (bDrop)
{
dataProvider.Unparent();
dropTarget.Items.Add(dragSourceObject);
}
e.Effects = DragDropEffects.Move;
e.Handled = true;
#if PRINT2OUTPUT
Debug.WriteLine(" Move2");
#endif
}
else
{
e.Effects = DragDropEffects.None;
e.Handled = true;
#if PRINT2OUTPUT
Debug.WriteLine(" None2");
#endif
}
}
}
if (bDrop && e.Handled && (e.Effects != DragDropEffects.None))
{
dragSourceObject.IsSelected = true;
dragSourceObject.BringIntoView();
}
}
}
