/// <summary>
/// Creates an instance of this view model with given parameteres
/// </summary>
/// <param name="parent">parent FpcWindowVm instance</param>
/// <param name="container">(sub)item in fpc state in which this vm desires to go</param>
/// <param name="containment">toolbox item that contains the data which is being dragged onto the state</param>
public DropIndicatorVm(FpcWindowVm parent, TreeItemVm container, IToolboxData containment)
: base(parent)
{
Container = container;
Containment = containment;
IsDropIndicator = true;
}
/// <summary>
/// Removes the current drop indicator from its container
/// </summary>
public void RemoveDropIndicator()
{
if (_dropIndicator != null)
{
_dropIndicator.Container.ContentsList.Remove(_dropIndicator);
_dropIndicator = null;
}
}
/// <summary>
/// Adds or removes the drap indicator object according to the tree item under the mouse
/// </summary>
/// <param name="pos_drawingArea">relative location of mouse in drawing area</param>
public void UpdateDropIndicator(Point pos_drawingArea)
{
//find the underlying tree item
TreeItemVm item = null;
if (SelectedToolboxItem.ContentData is StationVm)
item = SelectedToolboxItem.GetUnderlyingStateConfig(pos_drawingArea);
else if (SelectedToolboxItem.ContentData is ActivityVm)
item = SelectedToolboxItem.GetUnderlyingStateStation(pos_drawingArea);
else if (SelectedToolboxItem.ContentData is MachineVm)
item = SelectedToolboxItem.GetUnderlyingStateStationActivity(pos_drawingArea);
//remove the indicator if can't drop
if (item == null)
{
SelectedToolboxItem.CanDrop = false;
RemoveDropIndicator();
}
//add an indicator if can drop (transition from can't drop)
else if (!item.ContentsList.Any(x => x.IsDropIndicator))
{
SelectedToolboxItem.CanDrop = true;
_dropIndicator = new DropIndicatorVm(this, item, SelectedToolboxItem.ContentData);
item.ContentsList.Add(_dropIndicator);
}
}