/// <summary>
///
/// </summary>
/// <param name="eventPointExtractor"></param>
/// <returns>whether the event is handled</returns>
private bool HandleDrag(Func <IInputElement, Point> eventPointExtractor)
{
AnnotationGridVM agVM = DataContext as AnnotationGridVM;
if (agVM != null)
{
if (agVM.DragCandidateItem != null)
{
Point localOffset = agVM.LocalDraggedItemOffset;
Point curLocation = eventPointExtractor(LowerGrid);
double proposedLeft = curLocation.X - localOffset.X;
double proposedTop = curLocation.Y - localOffset.Y;
Vector move = agVM.DragItemInitialLocation - new Point(proposedLeft, proposedTop);
if (move.LengthSquared > 600 && agVM.DraggedItem == null)
{
//move far enough to trigger drag
//candidate is promoted to be actually dragged
agVM.DraggedItem = agVM.DragCandidateItem;
//System.Diagnostics.Trace.WriteLine(string.Format("Elem drag started at {0}:{1} as movement was {2:#.##}", proposedLeft, proposedTop, move.Length));
}
if (agVM.DraggedItem != null)
{
//actually moving dragged item on canvas
DraggedItemLeft = proposedLeft;
DraggedItemTop = proposedTop;
}
return(true);
}
}
return(false);
}
private bool HandleDragEnd(Func <IInputElement, Point> eventPointExtractor)
{
AnnotationGridVM agVM = DataContext as AnnotationGridVM;
if (agVM != null)
{
if (agVM.DraggedItem != null)
{
Point localOffset = agVM.LocalDraggedItemOffset;
Point curLocation = eventPointExtractor(ColumnsGrid);
Point droppedLocation = new Point(
curLocation.X - localOffset.X + agVM.DraggedItem.ActualWidth / 2, //X coord is the location of the centre of the dragged element
curLocation.Y - localOffset.Y); //Y coord is a top of the dragged element
if (isMouseCaptured)
{
//ReleaseMouseCapture();
System.Diagnostics.Trace.WriteLine("Mouse release");
isMouseCaptured = false;
}
int col = -1;
var htResult = VisualTreeHelper.HitTest(ColumnsGrid, droppedLocation);
if (htResult != null)
{
foreach (UIElement elem in ColumnsGrid.Children)
{
if (IsInVisualTree(htResult.VisualHit, elem))
{
col = Grid.GetColumn(elem);
}
}
}
ElementDropped?.Invoke(this, new ElemDroppedEventArgs(agVM.DraggedItem, col, droppedLocation.Y));
agVM.DraggedItem = null;
return(true);
}
}
return(false);
}
private static void DataContexChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
AnnotationGridVM oldVM = e.NewValue as AnnotationGridVM;
AnnotationGrid view = (AnnotationGrid)d;
if (oldVM != null)
{
oldVM.Columns.CollectionChanged -= view.Columns_CollectionChanged;
//TODO: handle columns removal
}
AnnotationGridVM newVM = e.NewValue as AnnotationGridVM;
if (newVM != null)
{
newVM.Columns.CollectionChanged += view.Columns_CollectionChanged;
foreach (ColumnVM colVM in newVM.Columns)
{
view.HandleColumnAdded(colVM);
}
}
}
/// <summary>
///
/// </summary>
/// <param name="eventPointExtractor"></param>
/// <returns>whether the event is handled</returns>
private bool HandleDrag(Func <IInputElement, Point> eventPointExtractor)
{
AnnotationGridVM agVM = DataContext as AnnotationGridVM;
if (agVM != null)
{
if (agVM.DraggedItem != null)
{
Point localOffset = agVM.LocalDraggedItemOffset;
Point curLocation = eventPointExtractor(LowerGrid);
DraggedItemLeft = curLocation.X - localOffset.X;
DraggedItemTop = curLocation.Y - localOffset.Y;
System.Diagnostics.Trace.WriteLine(string.Format("Elem moved to {0}:{1}", DraggedItemLeft, DraggedItemTop));
if (!isMouseCaptured)
{
//CaptureMouse();
System.Diagnostics.Trace.WriteLine("Mouse captured");
isMouseCaptured = true;
}
return(true);
}
}
return(false);
}
