/// <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>
internal 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);
}
/// <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>
internal 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);
}
