Deleting specific Attributes in a XML File (ASP.NET)

I just wrote a small guestbook for my website and decided to use a XML file instead of a Database. I came accross several problems. That’s how I solved them.
That’s my example xml file:

<?xml version="1.0" encoding="utf-8"?>
<slGuestbook>
<entry name="testy" email="sersmail" location="locylocy" date="31.07.2005 14:45:11">exampletxt</entry>
<entry name="testy" email="testq" location="locylocy" date="31.07.2005 14:44:57">exampletxt</entry>
</slGuestbook>

That's my function:

    public static XmlNode GetNode(XmlNode parentNode, string attrName, string attrValue)
        {
            XmlNode tmpNode = parentNode;
            XmlAttribute tmpAttr = null;


            while ((tmpAttr == null) && (tmpNode != null))
            {
                while ((tmpNode != null) && (tmpNode.LocalName != "entry"))
                    tmpNode = slGuestbook.NextNode(tmpNode);

                try
                {
                    tmpAttr = (XmlAttribute)tmpNode.Attributes.GetNamedItem(attrName);
                    if (tmpAttr.Value == attrValue)
                    {
                        return tmpNode;
                    }
                    else
                    {
                        tmpAttr = null;
                        tmpNode = slGuestbook.NextNode(tmpNode);
                    }
                }
                catch
                {
                    tmpAttr = null;
                }
            }

            return tmpNode;
        }

        #region Method NextNode()
        /// <summary>
        /// Method to jump to next node. It´s irrelevant if next node is a child or parent node.
        /// </summary>
        /// <param name="actNode">Actual Node.</param>
        /// <returns>Next Node if exists, else null (end of XML!).</returns>
        public static XmlNode NextNode(XmlNode actNode)
        {
            if (actNode.HasChildNodes)
            {
                return actNode.FirstChild;
            }

            try
            {
                if (actNode.NextSibling != null)
                {
                    actNode = actNode.NextSibling;
                }
                else
                {
                    actNode = actNode.ParentNode;

                    while (actNode.NextSibling == null)
                        actNode = actNode.ParentNode;

                    actNode = actNode.NextSibling;
                }
            }
            catch
            {
                actNode = null;
            }
            return actNode;
        }
        #endregion

And that's how I call it:

            string path = Server.MapPath("~/xml/guestbook.xml");

            XmlDocument doc = new XmlDocument();
            doc.Load(path);
            XmlNode parentNode = doc.DocumentElement;
            XmlNode toDelete = slGuestbook.GetNode(parentNode, "email", "testq");
            parentNode.RemoveChild(toDelete);
            doc.Save(path);

That’s working great for deleting specific guestbook entries. You can implent that call in any type of front-end to be able to delete entries on the fly.

Andreas Kraus
http://www.sunlab.de