/// <summary>
/// Creates a line which joins the parent NodeControl to the join line
/// </summary>
private void AddParentToChildLine(double left, double top, FrameworkElement control, HierarchyNode node)
{
double center = left + (control.Width / 2);
double lineTop = top + control.Height;
AddLine(center, center, lineTop, lineTop + (LevelSpacing / 2), node);
}
/// <summary>
/// Recursive method which adds the HierarchyNode controls and lines used to create the tree
/// </summary>
/// <param name="top">Top margin of the NodeControl</param>
/// <param name="left">Left margin of the NodeControl</param>
/// <param name="node">Node used to reference the NodeControl and children to display</param>
/// <param name="nodeHasParents">used to notify method that the node has no parents</param>
/// <returns></returns>
private double AddControl(double top, double left, HierarchyNode node, bool nodeHasParents)
{
double controlLeft = left;
FrameworkElement nodeControl = node.Control;
//Determine the placement and display all children first
if (node.Children.Count > 0)
{
double lineTop = top + nodeControl.Height + (LevelSpacing / 2);
double childTop = top + nodeControl.Height + LevelSpacing;
double childLeft = left;
//Add child controls to canvas first
foreach(HierarchyNode child in node.Children)
childLeft = AddControl(childTop, childLeft, child, true);
//Create horizontal join line to visually join children to parent
double firstNodePoint = node.Children.First().Control.Margin.Left + (node.Children.First().Control.Width / 2);
double lastNodePoint = node.Children.Last().Control.Margin.Left + (node.Children.Last().Control.Width / 2);
AddLine(firstNodePoint, lastNodePoint, lineTop, lineTop, node);
//Find center of join line to create parent line
double centerPoint = firstNodePoint + ((lastNodePoint - firstNodePoint) / 2);
controlLeft = centerPoint - (nodeControl.Width / 2);
left = childLeft + ChildSpacing;
}
else
{
//Node has no children so no need to recalculate left position of NodeControl
left += nodeControl.Width + ChildSpacing;
}
//Visually join node to parent
if (nodeHasParents)
AddChildToParentLine(controlLeft, top, nodeControl, node);
//Visually join node to children
if (node.Children.Count > 0)
AddParentToChildLine(controlLeft, top, nodeControl, node);
//Finally add NodeControl to canvas
nodeControl.Margin = new Thickness(controlLeft, top, 0, 0);
LayoutRoot.Children.Add(node.Control);
if (double.IsNaN(LayoutRoot.Height) || LayoutRoot.Height < top + nodeControl.Height + 10)
LayoutRoot.Height = top + nodeControl.Height + ChildSpacing;
return left;
}
/// <summary>
/// Refactored method used to display lines in the tree
/// </summary>
private void AddLine(double x1, double x2, double y1, double y2, HierarchyNode node)
{
Line newLine = new Line();
newLine.X1 = x1;
newLine.X2 = x2;
newLine.Y1 = y1;
newLine.Y2 = y2;
newLine.Stroke = this.lineBrush;
newLine.Tag = node;
LayoutRoot.Children.Add(newLine);
}
/// <summary>
/// Creates a line which joins the child NodeControl to the join line
/// </summary>
private void AddChildToParentLine(double left, double top, FrameworkElement control, HierarchyNode node)
{
double center = left + (control.Width / 2);
AddLine(center, center, top - (LevelSpacing / 2), top, node);
}