/// <summary>
/// Bring the collection of nodes into view.
/// This affects ContentViewportOffsetX/ContentViewportOffsetY, but doesn't affect 'ContentScale'.
/// </summary>
public void BringNodesIntoView(ICollection nodes)
{
if (nodes == null)
{
throw new ArgumentNullException("'nodes' argument shouldn't be null.");
}
if (nodes.Count == 0)
{
return;
}
Rect rect = Rect.Empty;
foreach (var node in nodes)
{
NodeItem nodeItem = FindAssociatedNodeItem(node);
Rect nodeRect = new Rect(nodeItem.X, nodeItem.Y, nodeItem.ActualWidth, nodeItem.ActualHeight);
if (rect == Rect.Empty)
{
rect = nodeRect;
}
else
{
rect.Intersect(nodeRect);
}
}
this.BringIntoView(rect);
}
/// <summary>
/// Find the max ZIndex of all the nodes.
/// </summary>
internal int FindMaxZIndex()
{
if (this.nodeItemsControl == null)
{
return(0);
}
int maxZ = 0;
for (int nodeIndex = 0; ; ++nodeIndex)
{
NodeItem nodeItem = (NodeItem)this.nodeItemsControl.ItemContainerGenerator.ContainerFromIndex(nodeIndex);
if (nodeItem == null)
{
break;
}
if (nodeItem.ZIndex > maxZ)
{
maxZ = nodeItem.ZIndex;
}
}
return(maxZ);
}
/// <summary>
/// Find the NodeItem UI element that is associated with 'node'.
/// 'node' can be a view-model object, in which case the visual-tree
/// is searched for the associated NodeItem.
/// Otherwise 'node' can actually be a 'NodeItem' in which case it is
/// simply returned.
/// </summary>
internal NodeItem FindAssociatedNodeItem(object node)
{
NodeItem nodeItem = node as NodeItem;
if (nodeItem == null)
{
nodeItem = nodeItemsControl.FindAssociatedNodeItem(node);
}
return(nodeItem);
}
/// <summary>
/// Event raised while the user is dragging a node.
/// </summary>
private void NodeItem_Dragging(object source, NodeDraggingEventArgs e)
{
e.Handled = true;
//
// Cache the NodeItem for each selected node whilst dragging is in progress.
//
if (this.cachedSelectedNodeItems == null)
{
this.cachedSelectedNodeItems = new List <NodeItem>();
foreach (var selectedNode in this.SelectedNodes)
{
NodeItem nodeItem = FindAssociatedNodeItem(selectedNode);
if (nodeItem == null)
{
throw new ApplicationException("Unexpected code path!");
}
this.cachedSelectedNodeItems.Add(nodeItem);
}
}
//
// Update the position of the node within the Canvas.
//
foreach (var nodeItem in this.cachedSelectedNodeItems)
{
nodeItem.X += e.HorizontalChange;
nodeItem.Y += e.VerticalChange;
}
var eventArgs = new NodeDraggingEventArgs(NodeDraggingEvent, this, this.SelectedNodes, e.HorizontalChange, e.VerticalChange);
RaiseEvent(eventArgs);
}