Tools.XmlConfigMerge.ConfigFileManager.UpdateExistingElementsAndAttribsRecurse C# (CSharp) Method

		private static void UpdateExistingElementsAndAttribsRecurse(XmlNodeList fromNodes, XmlNode toParentNode)
        {
			int iSameElement = 0;
			XmlNode lastElement = null;
			
            foreach (XmlNode node in fromNodes)
            {
				if (node.NodeType != XmlNodeType.Element)
                {
					continue;
				}

				if (lastElement != null
						&& node.Name == lastElement.Name && node.NamespaceURI == lastElement.NamespaceURI)
                {
					iSameElement++;
				}
                else
                {
					iSameElement = 0;
				}
				
                lastElement = node;
				
				XmlNode toNode;
				
                if (node.Attributes["key"] != null)
                {
					toNode = SelectSingleNodeMatchingNamespaceURI(toParentNode, node, node.Attributes["key"] );
				}
                else if (node.Attributes["name"] != null)
                {
					toNode = SelectSingleNodeMatchingNamespaceURI(toParentNode, node, node.Attributes["name"] );
				}
                else if (node.Attributes["type"] != null)
                {					
					toNode = SelectSingleNodeMatchingNamespaceURI(toParentNode, node, node.Attributes["type"] );
				}
                else
                {
					toNode = SelectSingleNodeMatchingNamespaceURI(toParentNode, node, iSameElement);
				}
				
				if (toNode == null)
                {
					if (node == null)
					{
						throw new ApplicationException("node == null");
					}
					
                    if (node.Name == null)
					{
						throw new ApplicationException("node.Name == null");
					}
					
                    if (toParentNode == null)
					{
						throw new ApplicationException("toParentNode == null");
					}
					
                    if (toParentNode.OwnerDocument == null)
					{
						throw new ApplicationException("toParentNode.OwnerDocument == null");
					}
									
					Debug.WriteLine("app: " + toParentNode.Name + "/" + node.Name);			
					
                    if (node.ParentNode.Name != toParentNode.Name)
                    {
						throw new ApplicationException("node.ParentNode.Name != toParentNode.Name: " + node.ParentNode.Name + " !=" + toParentNode.Name);
					}
					
                    try
                    {
						toNode = toParentNode.AppendChild(toParentNode.OwnerDocument.CreateElement(node.Name) );
					}
                    catch (Exception ex)
                    {
						throw new ApplicationException("ex during toNode = toParentNode.AppendChild(: " + ex.Message);
					}
				}
				
				//Copy element content if any
				XmlNode textEl = GetTextElement(node);

				if (textEl != null)
                {
					toNode.InnerText = textEl.InnerText;
				}
				
				//Copy attribs if any
				foreach (XmlAttribute attrib in node.Attributes)
                {
					XmlAttribute toAttrib = toNode.Attributes[attrib.Name];
					
                    if (toAttrib == null)
                    {
						Debug.WriteLine("attr: " + toNode.Name + "@" + attrib.Name);
						toAttrib = toNode.Attributes.Append(toNode.OwnerDocument.CreateAttribute(attrib.Name));
					}
					
                    toAttrib.InnerText = attrib.InnerText;
				}
				
                ((XmlElement) toNode).IsEmpty = ! toNode.HasChildNodes; //Ensure no endtag when not needed
				UpdateExistingElementsAndAttribsRecurse(node.ChildNodes, toNode);
			}
		}