XElement extension for proper retrieval of elements and attributes including better exception handling

XElementUtils.cs

using System;
using System.Globalization;
using System.Xml.Linq;

namespace YourNS
{
    public static class Utils
    {
        #region Attribute Helper

        /// <exception cref="ArgumentException"></exception>
        public static string GetAttributeOrThrow(this XElement element, string attribute)
        {
            var attr = element.Attribute(attribute);
            if (attr == null)
            {
                throw new ArgumentException(string.Format("Could not read attribute '{0}' from element {1}", attribute, element));
            }
            return attr.Value;
        }

        public static T GetAttributeOrDefault<T>(this XElement e, string attr, T def = default(T))
        {
            var a = e.Attribute(attr);
            if (a == null)
            {
                return def;
            }
            return (T) Convert.ChangeType(a.Value, typeof (T), CultureInfo.InvariantCulture);
        }

        #endregion



        #region Element Helper

        /// <exception cref="ArgumentException"></exception>
        public static string GetElementOrThrow(this XElement element, string elementName)
        {
            if (element == null)
            {
               throw new ArgumentException("Passed element was null");
            }
            var newE = element.Element(elementName);
            if (newE == null)
            {
                throw new ArgumentException(string.Format("Could not get element  '{0}' from element {1}", elementName, element));
            }
            return newE.Value;
        }

        /// <exception cref="ArgumentException"></exception>
        public static T GetElementConvertedOrThrow<T>(this XElement element, string elementName)
        {
            var newE = element.Element(elementName);
            if (newE == null)
            {
                throw new ArgumentException(string.Format("Could not get element  '{0}' from element {1}", elementName, element));
            }
            try
            {
                return (T)Convert.ChangeType(newE.Value, typeof(T), CultureInfo.InvariantCulture);
            }
            catch (Exception e)
            {
                throw new ArgumentException(string.Format("Could not get convert value '{0}' from element name {1} to type {2} from  element {3}. Resulting exception: {4}", newE, elementName, typeof(T), element, e));
            }
           
        }

        public static T GetElementOrDefaultIfNotExist<T>(this XElement e, string elementName, T def = default(T))
        {
            var a = e.Element(elementName);
            if (a == null)
            {
                return def;
            }
            var underlying = Nullable.GetUnderlyingType(typeof(T));

            // Handle nullables properly
            if (underlying != typeof(T))
            {
                // This is a nullable property
                return (T)Convert.ChangeType(a.Value, underlying, CultureInfo.InvariantCulture);
            }

            return (T) Convert.ChangeType(a.Value, typeof (T), CultureInfo.InvariantCulture);
        }

        #endregion

    }
}