MultilingualString.cs

public class MultilingualString
    {
        private const string TranslationsNode = "translations";
        private const string TranslationNode = "translation";
        private const string LanguageNode = "language";
        private const string ValueNode = "value";

        private IDictionary<string, string> _translations;

        #region Properties

        /// <summary>
        /// Gets or sets the serialized XML of all <see cref="Translations"/>
        /// </summary>
        public string Value { get; set; }
        
        //[NotMapped]
        private IDictionary<string, string> Translations
        {
            get { return _translations ?? (_translations = FromXml(Value)); }
        }

        /// <summary>
        /// Gets or sets the element with the specified key. 
        /// </summary>
        /// <returns>
        /// The element with the specified key.
        /// </returns>
        /// <param name="key">The key of the element to get or set.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception><exception cref="T:System.Collections.Generic.KeyNotFoundException">The property is retrieved and <paramref name="key"/> is not found.</exception><exception cref="T:System.NotSupportedException">The property is set and the <see cref="T:System.Collections.Generic.IDictionary`2"/> is read-only.</exception>
        public string this[string key]
        {
            get
            {
                if (ContainsKey(key))
                    return Translations[key];
                return string.Empty;
            }
            set
            {
                Translations[key] = value;
                UpdateValue();
            }
        }

        /// <summary>
        /// Gets an <see cref="T:System.Collections.Generic.ICollection`1"/> containing the keys of the <see cref="T:System.Collections.Generic.IDictionary`2"/>.
        /// </summary>
        /// <returns>
        /// An <see cref="T:System.Collections.Generic.ICollection`1"/> containing the keys of the object that implements <see cref="T:System.Collections.Generic.IDictionary`2"/>.
        /// </returns>
        public ICollection<string> Keys
        {
            get { return Translations.Keys; }
        }

        /// <summary>
        /// Gets an <see cref="T:System.Collections.Generic.ICollection`1"/> containing the values in the <see cref="T:System.Collections.Generic.IDictionary`2"/>.
        /// </summary>
        /// <returns>
        /// An <see cref="T:System.Collections.Generic.ICollection`1"/> containing the values in the object that implements <see cref="T:System.Collections.Generic.IDictionary`2"/>.
        /// </returns>
        public ICollection<string> Values
        {
            get { return Translations.Values; }
        }

        /// <summary>
        /// Gets the number of elements contained in the <see cref="T:System.Collections.Generic.ICollection`1"/>.
        /// </summary>
        /// <returns>
        /// The number of elements contained in the <see cref="T:System.Collections.Generic.ICollection`1"/>.
        /// </returns>
        public int Count
        {
            get { return Translations.Count; }
        }

        /// <summary>
        /// Gets a value indicating whether the <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only.
        /// </summary>
        /// <returns>
        /// true if the <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only; otherwise, false.
        /// </returns>
        public bool IsReadOnly
        {
            get { return Translations.IsReadOnly; }
        }

        #endregion

        /// <summary>
        /// Returns an enumerator that iterates through the collection.
        /// </summary>
        /// <returns>
        /// A <see cref="T:System.Collections.Generic.IEnumerator`1"/> that can be used to iterate through the collection.
        /// </returns>
        public IEnumerator<KeyValuePair<string, string>> GetEnumerator()
        {
            return _translations.GetEnumerator();
        }

        /// <summary>
        /// Adds an item to the <see cref="T:System.Collections.Generic.ICollection`1"/>.
        /// </summary>
        /// <param name="item">The object to add to the <see cref="T:System.Collections.Generic.ICollection`1"/>.</param><exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only.</exception>
        public void Add(KeyValuePair<string, string> item)
        {
            Translations.Add(item);
            UpdateValue();
        }

        /// <summary>
        /// Removes all items from the <see cref="T:System.Collections.Generic.ICollection`1"/>.
        /// </summary>
        /// <exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only. </exception>
        public void Clear()
        {
            Translations.Clear();
            UpdateValue();
        }

        /// <summary>
        /// Determines whether the <see cref="T:System.Collections.Generic.ICollection`1"/> contains a specific value.
        /// </summary>
        /// <returns>
        /// true if <paramref name="item"/> is found in the <see cref="T:System.Collections.Generic.ICollection`1"/>; otherwise, false.
        /// </returns>
        /// <param name="item">The object to locate in the <see cref="T:System.Collections.Generic.ICollection`1"/>.</param>
        public bool Contains(KeyValuePair<string, string> item)
        {
            return Translations.Contains(item);
        }

        /// <summary>
        /// Determines whether the <see cref="T:System.Collections.Generic.ICollection`1"/> contains a specific language.
        /// </summary>
        /// <returns>
        /// true if <paramref name="language"/> is found in the <see cref="T:System.Collections.Generic.ICollection`1"/>; otherwise, false.
        /// </returns>
        /// <param name="language">The object to locate in the <see cref="T:System.Collections.Generic.ICollection`1"/>.</param>
        public bool ContainsLanguage(string language)
        {
            return ContainsKey(language);
        }

        /// <summary>
        /// Copies the elements of the <see cref="T:System.Collections.Generic.ICollection`1"/> to an <see cref="T:System.Array"/>, starting at a particular <see cref="T:System.Array"/> index.
        /// </summary>
        /// <param name="array">The one-dimensional <see cref="T:System.Array"/> that is the destination of the elements copied from <see cref="T:System.Collections.Generic.ICollection`1"/>. The <see cref="T:System.Array"/> must have zero-based indexing.</param><param name="arrayIndex">The zero-based index in <paramref name="array"/> at which copying begins.</param><exception cref="T:System.ArgumentNullException"><paramref name="array"/> is null.</exception><exception cref="T:System.ArgumentOutOfRangeException"><paramref name="arrayIndex"/> is less than 0.</exception><exception cref="T:System.ArgumentException">The number of elements in the source <see cref="T:System.Collections.Generic.ICollection`1"/> is greater than the available space from <paramref name="arrayIndex"/> to the end of the destination <paramref name="array"/>.</exception>
        public void CopyTo(KeyValuePair<string, string>[] array, int arrayIndex)
        {
            Translations.CopyTo(array, arrayIndex);
        }

        /// <summary>
        /// Removes the first occurrence of a specific object from the <see cref="T:System.Collections.Generic.ICollection`1"/>.
        /// </summary>
        /// <returns>
        /// true if <paramref name="item"/> was successfully removed from the <see cref="T:System.Collections.Generic.ICollection`1"/>; otherwise, false. This method also returns false if <paramref name="item"/> is not found in the original <see cref="T:System.Collections.Generic.ICollection`1"/>.
        /// </returns>
        /// <param name="item">The object to remove from the <see cref="T:System.Collections.Generic.ICollection`1"/>.</param><exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only.</exception>
        public bool Remove(KeyValuePair<string, string> item)
        {
            bool removed = Translations.Remove(item);
            UpdateValue();
            return removed;
        }

        /// <summary>
        /// Determines whether the <see cref="T:System.Collections.Generic.IDictionary`2"/> contains an element with the specified key.
        /// </summary>
        /// <returns>
        /// true if the <see cref="T:System.Collections.Generic.IDictionary`2"/> contains an element with the key; otherwise, false.
        /// </returns>
        /// <param name="key">The key to locate in the <see cref="T:System.Collections.Generic.IDictionary`2"/>.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception>
        public bool ContainsKey(string key)
        {
            return Translations.ContainsKey(key);
        }

        /// <summary>
        /// Adds an element with the provided key and value to the <see cref="T:System.Collections.Generic.IDictionary`2"/>.
        /// </summary>
        /// <param name="key">The object to use as the key of the element to add.</param><param name="value">The object to use as the value of the element to add.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception><exception cref="T:System.ArgumentException">An element with the same key already exists in the <see cref="T:System.Collections.Generic.IDictionary`2"/>.</exception><exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.IDictionary`2"/> is read-only.</exception>
        public void Add(string key, string value)
        {
            Translations.Add(key, value);
            UpdateValue();
        }

        /// <summary>
        /// Removes the element with the specified key from the <see cref="T:System.Collections.Generic.IDictionary`2"/>.
        /// </summary>
        /// <returns>
        /// true if the element is successfully removed; otherwise, false.  This method also returns false if <paramref name="key"/> was not found in the original <see cref="T:System.Collections.Generic.IDictionary`2"/>.
        /// </returns>
        /// <param name="key">The key of the element to remove.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception><exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.IDictionary`2"/> is read-only.</exception>
        public bool Remove(string key)
        {
            bool removed = Translations.Remove(key);
            UpdateValue();
            return removed;
        }

        /// <summary>
        /// Gets the value associated with the specified key.
        /// </summary>
        /// <returns>
        /// true if the object that implements <see cref="T:System.Collections.Generic.IDictionary`2"/> contains an element with the specified key; otherwise, false.
        /// </returns>
        /// <param name="key">The key whose value to get.</param><param name="value">When this method returns, the value associated with the specified key, if the key is found; otherwise, the default value for the type of the <paramref name="value"/> parameter. This parameter is passed uninitialized.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception>
        public bool TryGetValue(string key, out string value)
        {
            return Translations.TryGetValue(key, out value);
        }

        private void UpdateValue()
        {
            Value = ToXml(_translations);
        }

        private IDictionary<string, string> FromXml(string value)
        {
            if (value == null)
                return new Dictionary<string, string>();
            return
                XElement.Parse(value)
                        .Elements()
                        .ToDictionary(t =>
                        {
                            var languageContent = t.Element(LanguageNode);
                            Debug.Assert(languageContent != null, "Could not load language in " + this);
                            return languageContent.Value;
                        },
                            t =>
                            {
                                var valueContent = t.Element(ValueNode);
                                Debug.Assert(valueContent != null, "Could not load value in " + this);
                                return valueContent.Value;
                            });
        }

        private string ToXml(IEnumerable<KeyValuePair<string, string>> translations)
        {
            var translationsXml = new XElement(TranslationsNode);
            foreach (var translationXml in from keyValuePair in translations let keyXml = new XElement(LanguageNode, keyValuePair.Key) let valueXml = new XElement(ValueNode, keyValuePair.Value) select new XElement(TranslationNode, keyXml, valueXml))
            {
                translationsXml.Add(translationXml);
            }
            return translationsXml.ToString(SaveOptions.DisableFormatting);
        }

        /// <summary>
        /// Returns a string that represents the current object.
        /// </summary>
        /// <returns>
        /// A string that represents the current object.
        /// </returns>
        public override string ToString()
        {
            return string.Format("Translations: {0}, Id: {1}, Value: {2}", _translations, Id, Value);
        }
    }