/// <summary>
/// Applies a horizontal offset to the dragged <see cref="DockTabItem"/>s.
/// </summary>
private void SetTranslateTransform()
{
Debug.Assert(_targetDockTabPane != null);
double?offset = null;
for (int i = 0; i < _targetDockTabPane.Items.Count; i++)
{
var dockTabItem = _targetDockTabPane.ItemContainerGenerator.ContainerFromIndex(i) as DockTabItem;
if (dockTabItem == null)
{
continue; // Item container not yet generated.
}
if (!_draggedItems.Contains(dockTabItem.GetViewModel()))
{
continue; // Item is not dragged.
}
if (offset == null)
{
// The mouse cursor should be on the first dragged DockTabItem.
if (_mouseOffset.X < 0 || _mouseOffset.X > dockTabItem.RenderSize.Width)
{
if (dockTabItem.RenderSize.Width > 0)
{
_mouseOffset.X = dockTabItem.RenderSize.Width / 4;
}
else
{
_mouseOffset.X = 32; // Item not yet measured. Use default value.
}
}
Point mousePosition = WindowsHelper.GetMousePosition(dockTabItem);
offset = mousePosition.X - _mouseOffset.X;
}
// Set DockTabPanel.IsDragged flag. Items which are dragged are not animated
// by the DockTabPanel.
DockTabPanel.SetIsDragged(dockTabItem, true);
// Apply offset as RenderTransform.
var translateTransform = dockTabItem.RenderTransform as TranslateTransform;
if (translateTransform == null)
{
translateTransform = new TranslateTransform();
dockTabItem.RenderTransform = translateTransform;
}
translateTransform.X += offset.Value;
}
}
/// <summary>
/// Clears the horizontal offset from the dragged <see cref="DockTabItem"/>s.
/// </summary>
private void ClearTranslateTransform()
{
Debug.Assert(_targetDockTabPane != null);
for (int i = 0; i < _targetDockTabPane.Items.Count; i++)
{
var dockTabItem = _targetDockTabPane.ItemContainerGenerator.ContainerFromIndex(i) as DockTabItem;
if (dockTabItem != null && DockTabPanel.GetIsDragged(dockTabItem))
{
DockTabPanel.SetIsDragged(dockTabItem, false);
var translateTransform = dockTabItem.RenderTransform as TranslateTransform;
if (translateTransform != null)
{
translateTransform.X = 0;
}
}
}
}