void OnDragOver(object sender, DragEventArgs e)
{
// drag over is the only event which returns the position
// GiveFeedback returns nonsense even from Mouse.GetPosition
Point point = e.GetPosition(TreeView);
if (TryScroll(point))
{
return;
}
if (dragAdorner == null)//external drop
{
var content = new DragContent();
content.Add(e.Data);
dragAdorner = new DragAdorner(TreeView, content);
}
dragAdorner.UpdatePosition(point);
if (IsMouseOverAdorner(point))
{
return;
}
var itemsPresenter = TreeView.ScrollViewer.Content as ItemsPresenter;
if (itemsPresenter.InputHitTest(e.GetPosition(itemsPresenter)) == null)
{
dragAdorner.Content.CanDrop = false;
dragAdorner.Content.CanInsert = false;
//dragAdorner.Content.InsertIndex = -1;
if (insertAdorner != null)
{
insertAdorner.Dispose();
}
return;
}
if (itemMouseIsOver != null)
{
itemMouseIsOver.IsCurrentDropTarget = false;
}
itemMouseIsOver = GetTreeViewItemUnderMouse(point);
if (itemMouseIsOver == null)
{
return;
}
CanInsertReturn canInsertReturn = CanInsert(itemMouseIsOver, e.GetPosition, e.Data);
if (canInsertReturn != null)
{
dragAdorner.Content.CanDrop = false;
dragAdorner.Content.CanInsert = true;
//dragAdorner.Content.InsertIndex = canInsertReturn.Index;
if (insertAdorner == null)
{
insertAdorner = new InsertAdorner(itemMouseIsOver, new InsertContent {
Before = canInsertReturn.Before
});
}
else
{
insertAdorner.Dispose();
insertAdorner = new InsertAdorner(itemMouseIsOver, new InsertContent {
Before = canInsertReturn.Before
});
}
itemMouseIsOver.IsCurrentDropTarget = false;
}
else
{
dragAdorner.Content.CanInsert = false;
//dragAdorner.Content.InsertIndex = -1;
if (insertAdorner != null)
{
insertAdorner.Dispose();
insertAdorner = null;
}
dragAdorner.Content.CanDrop = CanDrop(itemMouseIsOver, e.Data) != null;
if (itemMouseIsOver != null)
{
itemMouseIsOver.IsCurrentDropTarget = true;
}
}
}
private void DragStart(DragContent dragData)
{
initialCursor = TreeView.Cursor;
autoScroller.IsEnabled = true;
if (dragAdorner == null)
{
dragAdorner = new DragAdorner(TreeView, dragData);
}
}
void OnDragOver(object sender, DragEventArgs e)
{
// drag over is the only event which returns the position
// GiveFeedback returns nonsense even from Mouse.GetPosition
Point point = e.GetPosition(TreeView);
if (TryScroll(point)) return;
if (dragAdorner == null)//external drop
{
var content = new DragContent();
content.Add(e.Data);
dragAdorner = new DragAdorner(TreeView, content);
}
dragAdorner.UpdatePosition(point);
if (IsMouseOverAdorner(point)) return;
var itemsPresenter = TreeView.ScrollViewer.Content as ItemsPresenter;
if (itemsPresenter.InputHitTest(e.GetPosition(itemsPresenter)) == null)
{
dragAdorner.Content.CanDrop = false;
dragAdorner.Content.CanInsert = false;
dragAdorner.Content.InsertIndex = -1;
if (insertAdorner != null) insertAdorner.Dispose();
return;
}
if (itemMouseIsOver != null)
{
itemMouseIsOver.IsCurrentDropTarget = false;
}
itemMouseIsOver = GetTreeViewItemUnderMouse(point);
if (itemMouseIsOver == null) return;
CanInsertReturn canInsertReturn = CanInsert(itemMouseIsOver, e.GetPosition, e.Data);
if (canInsertReturn != null)
{
dragAdorner.Content.CanDrop = false;
dragAdorner.Content.CanInsert = true;
dragAdorner.Content.InsertIndex = canInsertReturn.Index;
if (insertAdorner == null)
{
insertAdorner = new InsertAdorner(itemMouseIsOver, new InsertContent { Before = canInsertReturn.Before });
}
else
{
insertAdorner.Dispose();
insertAdorner = new InsertAdorner(itemMouseIsOver, new InsertContent { Before = canInsertReturn.Before });
}
itemMouseIsOver.IsCurrentDropTarget = false;
}
else
{
dragAdorner.Content.CanInsert = false;
dragAdorner.Content.InsertIndex = -1;
if (insertAdorner != null)
{
insertAdorner.Dispose();
insertAdorner = null;
}
dragAdorner.Content.CanDrop = CanDrop(itemMouseIsOver, e.Data) != null;
if (itemMouseIsOver != null)
{
itemMouseIsOver.IsCurrentDropTarget = true;
}
}
}
private void CleanUpAdorners()
{
if (dragAdorner != null)
{
// on external drop no cleanup method is called.
dragAdorner.Dispose();
dragAdorner = null;
}
if (insertAdorner != null)
{
insertAdorner.Dispose();
insertAdorner = null;
}
}