Bloom.Book.HtmlDom.MigrateChildren C# (CSharp) Method

        private static void MigrateChildren(XmlElement page, string parentClass, XmlElement newPage)
        {
            //the leading '.' here is needed because newPage is an element in a larger DOM, and we only want to search in this page
            var xpath = ".//div[contains(concat(' ', @class, ' '), ' " + parentClass + " ')]";
            var oldParents = page.SafeSelectNodes(xpath);
            var newParents = newPage.SafeSelectNodes(xpath);
            // The Math.Min is not needed yet; in fact, we don't yet have any cases where there is more than one
            // thing to copy or where the numbers are not equal. It's just a precaution.
            for(int i = 0; i < Math.Min(newParents.Count, oldParents.Count); i++)
            {
                var oldParent = (XmlElement) oldParents[i];
                var newParent = (XmlElement) newParents[i];
                foreach(var child in newParent.ChildNodes.Cast<XmlNode>().ToArray())
                    newParent.RemoveChild(child);
                // apparently we are modifying the ChildNodes collection by removing the child from there to insert in the new location,
                // which messes things up unless we make a copy of the collection.
                foreach(XmlNode child in oldParent.ChildNodes.Cast<XmlNode>().ToArray())
                {
                    newParent.AppendChild(child);
                    AddKnownStyleIfMissing(child);
                }
            }
        }