private void OnItemDragDrop(object sender, DragEventArgs e)
{
DragDropObject data = new DragDropObject(e.Data);
DragDropOption action = DragDropOption.None;
DragDropOption allowedActions = ConvertEnum.GetDragDropAction(e.AllowedEffect);
ModifierFlags modifiers = ConvertEnum.GetModifierFlags(e);
Point clientPoint = _listView.PointToClient(new Point(e.X, e.Y));
IGalleryItem targetItem;
bool skipNearestItem = false;
if (_component.AllowsDropOnItem)
{
targetItem = GetTargetItemAt(clientPoint, false);
if (targetItem != null)
{
action = _component.PerformDrop(data, targetItem, allowedActions, modifiers);
skipNearestItem = true;
if (action != DragDropOption.None)
{
DrawInsertionMark(_gallery.IndexOf(targetItem), true, clientPoint);
}
}
}
if (_component.AllowsDropAtIndex && action == DragDropOption.None)
{
int targetIndex = GetNearestTargetIndexAt(clientPoint);
if (targetIndex >= 0)
{
action = _component.PerformDrop(data, targetIndex, allowedActions, modifiers);
if (action != DragDropOption.None)
{
DrawInsertionMark(targetIndex, false, clientPoint);
}
}
}
if (!skipNearestItem && _component.AllowsDropOnItem && action == DragDropOption.None)
{
targetItem = GetTargetItemAt(clientPoint, true);
if (targetItem != null)
{
action = _component.PerformDrop(data, targetItem, allowedActions, modifiers);
if (action != DragDropOption.None)
{
DrawInsertionMark(_gallery.IndexOf(targetItem), true, clientPoint);
}
}
}
e.Effect = ConvertEnum.GetDragDropEffects(action);
DrawInsertionMark(-1, false, Point.Empty);
}
private void OnItemDrag(object sender, ItemDragEventArgs e)
{
List <IGalleryItem> list = new List <IGalleryItem>();
List <object> objectList = new List <object>();
ListViewItem specificLvi = (ListViewItem)e.Item;
IGalleryItem specificDraggedItem = (IGalleryItem)specificLvi.Tag;
// save selection and focus
IList savedSelection = new List <IGalleryItem>();
object savedFocus = _listView.FocusedItem.Tag;
if (_listView.SelectedItems.Count > 0)
{
foreach (ListViewItem lvi in _listView.SelectedItems)
{
IGalleryItem item = (IGalleryItem)lvi.Tag;
list.Add(item);
objectList.Add(item.Item);
savedSelection.Add(item);
}
}
else
{
list.Add(specificDraggedItem);
objectList.Add(specificDraggedItem.Item);
}
_selectionEventsEnabled = false;
IList <IGalleryItem> draggedItems = list.AsReadOnly();
DragDropOption allowedActions = _component.BeginDrag(draggedItems);
DragDropOption actualAction = DragDropOption.None;
if (allowedActions != DragDropOption.None)
{
DataObject data = new DataObject();
data.SetData(draggedItems); // for GalleryComponent consumers, provide a list of the items that were dragged
data.SetData(objectList.ToArray()); // for foreign consumers, provide an array of the objects wrapped by the dragged/selected items
data.SetData(specificDraggedItem); // for foreign consumers, provide the actual item that was dragged, not the selected ones
DragDropEffects allowedEffects = ConvertEnum.GetDragDropEffects(allowedActions);
DragDropEffects actualEffect = _listView.DoDragDrop(data, allowedEffects);
actualAction = ConvertEnum.GetDragDropAction(actualEffect);
}
_component.EndDrag(draggedItems, actualAction);
// restore selection and focus
_listView.SelectedIndices.Clear();
for (int n = 0; n < _listView.Items.Count; n++)
{
ListViewItem lvi = _listView.Items[n];
if (savedSelection.Contains(lvi.Tag))
{
_listView.SelectedIndices.Add(n);
savedSelection.Remove(lvi.Tag);
}
if (lvi.Tag == savedFocus)
{
lvi.Focused = true;
}
}
_selectionEventsEnabled = true;
// if any previously-selected items are left in the list, then the selection has changed overall and we need to update the component selection
if (savedSelection.Count > 0)
{
OnSelectionChanged(null, null);
}
}
