System.Xml.XPath.XPathNavigator.MoveToNonDescendant C# (CSharp) Method

        internal bool MoveToNonDescendant()
        {
            // If current node is document, there is no next non-descendant
            if (NodeType == XPathNodeType.Root)
                return false;

            // If sibling exists, it is the next non-descendant
            if (MoveToNext())
                return true;

            // The current node is either an attribute, namespace, or last child node
            XPathNavigator navSave = Clone();

            if (!MoveToParent())
                return false;

            switch (navSave.NodeType)
            {
                case XPathNodeType.Attribute:
                case XPathNodeType.Namespace:
                    // Next node in document order is first content-child of parent
                    if (MoveToFirstChild())
                        return true;
                    break;
            }

            while (!MoveToNext())
            {
                if (!MoveToParent())
                {
                    // Restore original position and return false
                    MoveTo(navSave);
                    return false;
                }
            }

            return true;
        }

        /// <summary>
        /// Position "nav" to the matching node which follows it in document order but is not a descendant node.
        /// Return false if this is no such matching node.
        /// </summary>
        internal static bool MoveFirst(XmlNavigatorFilter filter, XPathNavigator nav) {
            // Attributes and namespace nodes include descendants of their owner element in the set of following nodes
            if (nav.NodeType == XPathNodeType.Attribute || nav.NodeType == XPathNodeType.Namespace) {
                if (!nav.MoveToParent()) {
                    // Floating attribute or namespace node that has no following nodes
                    return false;
                }

                if (!filter.MoveToFollowing(nav, null)) {
                    // No matching following nodes
                    return false;
                }
            }
            else {
                // XPath spec doesn't include descendants of the input node in the following axis
                if (!nav.MoveToNonDescendant())
                    // No following nodes
                    return false;

                // If the sibling does not match the node-test, find the next following node that does
                if (filter.IsFiltered(nav)) {
                    if (!filter.MoveToFollowing(nav, null)) {
                        // No matching following nodes
                        return false;
                    }
                }
            }

            // Success
            return true;
        }