/// <summary>
/// Handles mouse move events when the drag operation is in progress.
/// </summary>
private void Drag()
{
Debug.Assert(IsDragging);
if (!_dragDeltaExceeded)
{
Point mousePosition = WindowsHelper.GetMousePosition(_dockControl);
Vector dragDelta = mousePosition - _initialMousePosition;
if (Math.Abs(dragDelta.X) > SystemParameters.MinimumHorizontalDragDistance ||
Math.Abs(dragDelta.Y) > SystemParameters.MinimumVerticalDragDistance)
{
_dragDeltaExceeded = true;
}
else
{
// Do nothing.
return;
}
}
if (_targetDockTabPane != null && IsMouseOver(_targetDockTabPane.GetItemsPanel(), VerticalTolerance))
{
// Drag items inside a DockTabPanel.
DragDockTabItems();
return;
}
if (_floatWindow == null)
{
// Move the items into a FloatWindow.
DragDockTabItemsIntoFloatWindow();
}
// Move the FloatWindow to the mouse position.
DragFloatWindow();
// Show DockIndicators and check possible dock positions.
UpdateDockIndicators();
if (!HasResult(_paneDockIndicators) && !HasResult(_borderDockIndicators))
{
// Check whether mouse cursor is over other DockTabItem tab and
// move items into DockTabPane.
DragFloatWindowIntoDockTabPanel();
}
}
/// <summary>
/// Gets the <see cref="DockTabItem"/> at the mouse position by testing against the
/// <see cref="DockTabItem"/> tabs in the specified pane.
/// </summary>
/// <param name="dockTabPane">The <see cref="DockTabPane"/>.</param>
/// <param name="verticalTolerance">
/// The tolerance (margin at top and bottom) in pixels.
/// </param>
/// <returns>The <see cref="DockTabItem"/> under the mouse cursor.</returns>
private static DockTabItem GetDockTabItemAtMouse(DockTabPane dockTabPane, double verticalTolerance = 0)
{
Debug.Assert(dockTabPane != null);
if (dockTabPane.Items.Count == 0)
{
return(null); // Empty DockTabPane.
}
var itemsPanel = dockTabPane.GetItemsPanel();
if (itemsPanel == null)
{
return(null); // ItemsPanel missing.
}
Point mousePosition = WindowsHelper.GetMousePosition(itemsPanel);
Rect bounds = new Rect(itemsPanel.RenderSize);
bounds.Inflate(0, verticalTolerance);
if (!bounds.Contains(mousePosition))
{
return(null); // Mouse position outside ItemsPanel.
}
// Test mouse position against DockTabItems bounds.
double height = itemsPanel.RenderSize.Height;
double x = 0;
for (int i = 0; i < dockTabPane.Items.Count; i++)
{
var dockTabItem = dockTabPane.ItemContainerGenerator.ContainerFromIndex(i) as DockTabItem;
if (dockTabItem == null)
{
break;
}
bounds = new Rect(new Point(x, 0), new Size(dockTabItem.RenderSize.Width, height));
bounds.Inflate(0, verticalTolerance);
if (bounds.Contains(mousePosition))
{
return(dockTabItem);
}
x += bounds.Width;
}
return(null);
}