How can I add a XmlNode to XmlNode List , if I have XmlNodeList and I want to create two XmlNodeList out of them.?

Question

I have one XmlNodeList, I want to create two XmlNodeList out of this. I will be checking for some tag inside each item in List, on the basis of that tag presence I will be adding them to one of the list which I have defined.

I was trying to add the list but I did not any method to add the particular item to a new XmlNodeList which is null in the start . Please help out. What I am missing here.

I have tried List<XmlNode> , it is throwing error System.ArgumentNullException: 'Value cannot be null. Parameter name: source'

class Program
    {
        static void Main(string[] args)
        {
            //Import XMl 
            // XmlNode list as name NEW

            foreach(XmlNode emp in NEW)
            {
                if (emp != null)
                {
                    AddNewList(emp);
                }

            }
        } 

        public static void AddNewList(XmlNode emp)
        {
            //Checking for some tag 
            if(tag!=null)
            {
                // It is throwing error 
                currentList.Append(emp);
            }
        }

        public XmlNodeList currentList = null;
        public XmlNodeList previousList = null;
    }
}

Answer 1

The only way to have items in XmlNodeList is to run selection query on XmlNode. There is no other way to construct XmlNodeList.

So the only option to "split" XmlNodeList in two XmlNodeList is to run separate XPath queries with opposite conditions that will select nodes into separate lists.

Note that XmlNodeList is not List<XmlNode> despite very similar name - adding to List<XmlNode> is indeed possible.