/// <summary>
/// Applies the selection box on the view to know the selected items.
/// </summary>
private void ApplySelectionBox()
{
// Clear selection.
this.ParentView.SelectedItems.Clear();
// Hidding the canvas hosting the selection box.
this.SelectionBoxCanvas.Visibility = Visibility.Collapsed;
this.SelectionBox.Visibility = Visibility.Collapsed;
double lX = Canvas.GetLeft(this.SelectionBox);
double lY = Canvas.GetTop(this.SelectionBox);
double lWidth = this.SelectionBox.Width;
double lHeight = this.SelectionBox.Height;
Rect lSelectionRect = new Rect(lX, lY, lWidth, lHeight);
// Inflate the drag selection-rectangle by 1/10 of its size to make sure the intended item is selected.
lSelectionRect.Inflate(lWidth / 10, lHeight / 10);
// Selecting the items contained in the selection rect.
if (this.ParentView.ItemsSource != null)
{
foreach (IGraphItemViewModel lItem in this.ParentView.ItemsSource)
{
// Getting the corresponding container.
AGraphItem lContainer = this.ParentView.GetContainerForViewModel(lItem);
if (lContainer != null)
{
if (lSelectionRect.Contains(lContainer.BoundingBox))
{
this.ParentView.SelectedItems.Add(lItem);
}
}
}
}
}
/// <summary>
/// Delegate called when the CanBeDragged property is modified.
/// </summary>
/// <param name="pSender">The item of interest.</param>
/// <param name="pEventArgs">The event arguments.</param>
private static void OnCanBeDraggedPropertyChanged(object pSender, DependencyPropertyChangedEventArgs pEventArgs)
{
AGraphItem lItem = pSender as AGraphItem;
bool lCanBeDragged = Convert.ToBoolean(pEventArgs.NewValue);
if (lItem != null)
{
if (lCanBeDragged)
{
lItem.MouseDown += OnItemMouseDown;
lItem.MouseMove += OnItemMouseMove;
lItem.MouseUp += OnItemMouseUp;
}
else
{
lItem.MouseDown -= OnItemMouseDown;
lItem.MouseMove -= OnItemMouseMove;
lItem.MouseUp -= OnItemMouseUp;
}
}
}
/// <summary>
/// Releases the dragged item as the drag process ends.
/// </summary>
private static void ReleaseDraggedItem()
{
if (sDraggedItem == null)
{
return;
}
SimpleGraphView lParentCanvas = sDraggedItem.FindVisualParent <SimpleGraphView>();
if (lParentCanvas == null)
{
return;
}
lParentCanvas.MouseMove -= OnParentCanvasMouseMove;
lParentCanvas.MouseUp -= OnParentCanvasMouseUp;
sDraggedItem.ReleaseMouseCapture();
sDraggedItem = null;
sDragStartPos = null;
}
/// <summary>
/// Delegate called when the mouse is down on a graph view item.
/// </summary>
/// <param name="pSender">The item of interest.</param>
/// <param name="pEventArgs">The event arguments.</param>
private static void OnItemMouseDown(object pSender, MouseButtonEventArgs pEventArgs)
{
AGraphItem lItem = pSender as AGraphItem;
if (lItem == null)
{
return;
}
SimpleGraphView lParentCanvas = lItem.FindVisualParent <SimpleGraphView>();
if (lParentCanvas == null)
{
return;
}
// Sometimes the mouse goes faster than the item. Its up to the canvas then to continue the drag
lParentCanvas.MouseMove += OnParentCanvasMouseMove;
lParentCanvas.MouseUp += OnParentCanvasMouseUp;
sDraggedItem = lItem;
sDragStartPos = pEventArgs.GetPosition(lItem);
lItem.CaptureMouse();
}
/// <summary>
/// Sets the property value for the given item.
/// </summary>
/// <param name="pItem">The item of interest.</param>
/// <param name="pValue">Flag indicating if the item can be dragged.</param>
public static void SetCanBeDragged(AGraphItem pItem, bool pValue)
{
pItem.SetValue(CanBeDraggedProperty, pValue);
}
/// <summary>
/// Returns the property value for the given item.
/// </summary>
/// <param name="pItem">The item of interest.</param>
/// <returns>True if it can be dragged, false otherwise.</returns>
public static bool GetCanBeDragged(AGraphItem pItem)
{
return((bool)pItem.GetValue(CanBeDraggedProperty));
}