/// <summary>
/// Gets the descendants of a node.
/// </summary>
/// <param name="tree">
/// The tree.
/// </param>
/// <param name="predicate">
/// The predicate.
/// </param>
/// <typeparam name="TNode">
/// The type of the tree node value
/// </typeparam>
/// <returns>
/// The <see cref="IEnumerable{TreeNode}"/>.
/// </returns>
public static IEnumerable <TreeNode <TNode> > Descendants <TNode>(
this TreeNode <TNode> tree,
Expression <Func <TreeNode <TNode>, bool> > predicate = null)
where TNode : IHasKeyId
{
var visitor = new NodeAggregatorTreeNodeVisitor <TNode>();
tree.Traverse(visitor);
// the visitor will pick up the tree itself in the traversal so we have to remove it
var nodes = visitor.Nodes.Where(x => x.Value.Key != tree.Value.Key).AsQueryable();
return(predicate == null ? nodes : nodes.Where(predicate));
}
/// <summary>
/// Gets the ancestors of a node including itself.
/// </summary>
/// <param name="tree">
/// The tree.
/// </param>
/// <param name="predicate">
/// The predicate.
/// </param>
/// <typeparam name="TNode">
/// The type of the tree node value
/// </typeparam>
/// <returns>
/// The <see cref="IEnumerable{TreeNode}"/>.
/// </returns>
public static IEnumerable <TreeNode <TNode> > AncestorsOrSelf <TNode>(
this TreeNode <TNode> tree,
Expression <Func <TreeNode <TNode>, bool> > predicate = null) where TNode : IHasKeyId
{
if (tree.Parent == null)
{
return(Enumerable.Empty <TreeNode <TNode> >());
}
var visitor = new NodeAggregatorTreeNodeVisitor <TNode>();
tree.Climb(visitor);
var nodes = visitor.Nodes.AsQueryable();
return(predicate == null ? nodes : nodes.Where(predicate));
}
