ObservableDictionary for Silverlight

I have reused copied the code from Shimmy's Blog but had to tweak it a bit to make it fit for Silverlight. At the moment I have used it just in one of my projects but works very well.

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Linq;

namespace SLUtils.Classes
{
        public class ObservableDictionary<TKey, TValue> : IDictionary<TKey, TValue>, INotifyCollectionChanged, INotifyPropertyChanged
        {
            private const string CountString = "Count";
            private const string IndexerName = "Item[]";
            private const string KeysName = "Keys";
            private const string ValuesName = "Values";

            private IDictionary<TKey, TValue> _Dictionary;
            protected IDictionary<TKey, TValue> Dictionary
            {
                get { return _Dictionary; }
            }

            #region Constructors
            public ObservableDictionary()
            {
                _Dictionary = new Dictionary<TKey, TValue>();
            }
            public ObservableDictionary(IDictionary<TKey, TValue> dictionary)
            {
                _Dictionary = new Dictionary<TKey, TValue>(dictionary);
            }
            public ObservableDictionary(IEqualityComparer<TKey> comparer)
            {
                _Dictionary = new Dictionary<TKey, TValue>(comparer);
            }
            public ObservableDictionary(int capacity)
            {
                _Dictionary = new Dictionary<TKey, TValue>(capacity);
            }
            public ObservableDictionary(IDictionary<TKey, TValue> dictionary, IEqualityComparer<TKey> comparer)
            {
                _Dictionary = new Dictionary<TKey, TValue>(dictionary, comparer);
            }
            public ObservableDictionary(int capacity, IEqualityComparer<TKey> comparer)
            {
                _Dictionary = new Dictionary<TKey, TValue>(capacity, comparer);
            }
            #endregion

            #region IDictionary<TKey,TValue> Members

            public void Add(TKey key, TValue value)
            {
                Insert(key, value, true);
            }

            public bool ContainsKey(TKey key)
            {
                return Dictionary.ContainsKey(key);
            }

            public ICollection<TKey> Keys
            {
                get { return Dictionary.Keys; }
            }

            public bool Remove(TKey key)
            {
                if (key == null) throw new ArgumentNullException("key");

                TValue value;
                Dictionary.TryGetValue(key, out value);

                int index = GetIndex(Dictionary, key);
                var removed = Dictionary.Remove(key);

                if (removed)
                    OnCollectionChanged(NotifyCollectionChangedAction.Remove, new KeyValuePair<TKey, TValue>(key, value), index);
                    //OnCollectionChanged();
                return removed;
            }

            public bool TryGetValue(TKey key, out TValue value)
            {
                return Dictionary.TryGetValue(key, out value);
            }

            public ICollection<TValue> Values
            {
                get { return Dictionary.Values; }
            }

            public TValue this[TKey key]
            {
                get
                {
                    return Dictionary[key];
                }
                set
                {
                    Insert(key, value, false);
                }
            }

            #endregion

            #region ICollection<KeyValuePair<TKey,TValue>> Members

            public void Add(KeyValuePair<TKey, TValue> item)
            {
                Insert(item.Key, item.Value, true);
            }

            public void Clear()
            {
                if (Dictionary.Count > 0)
                {
                    Dictionary.Clear();
                    OnCollectionChanged();
                }
            }

            public bool Contains(KeyValuePair<TKey, TValue> item)
            {
                return Dictionary.Contains(item);
            }

            public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
            {
                Dictionary.CopyTo(array, arrayIndex);
            }

            public int Count
            {
                get { return Dictionary.Count; }
            }

            public bool IsReadOnly
            {
                get { return Dictionary.IsReadOnly; }
            }

            public bool Remove(KeyValuePair<TKey, TValue> item)
            {
                return Remove(item.Key);
            }

            #endregion

            #region IEnumerable<KeyValuePair<TKey,TValue>> Members

            public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
            {
                return Dictionary.GetEnumerator();
            }

            #endregion

            #region IEnumerable Members

            IEnumerator IEnumerable.GetEnumerator()
            {
                return ((IEnumerable)Dictionary).GetEnumerator();
            }

            #endregion

            #region INotifyCollectionChanged Members

            public event NotifyCollectionChangedEventHandler CollectionChanged;

            #endregion

            #region INotifyPropertyChanged Members

            public event PropertyChangedEventHandler PropertyChanged;

            #endregion

            public void AddRange(IDictionary<TKey, TValue> items)
            {
                if (items == null) throw new ArgumentNullException("items");

                if (items.Count > 0)
                {
                    if (Dictionary.Count > 0)
                    {
                        if (items.Keys.Any((k) => Dictionary.ContainsKey(k)))
                            throw new ArgumentException("An item with the same key has already been added.");
                        else
                            foreach (var item in items) Dictionary.Add(item);
                    }
                    else
                        _Dictionary = new Dictionary<TKey, TValue>(items);

                    OnCollectionChanged(NotifyCollectionChangedAction.Add, items.ToArray(), GetIndex(Dictionary, items.Keys.First())); //We notify the index of the first added key
                }
            }

            private void Insert(TKey key, TValue value, bool add)
            {
                if (key == null) throw new ArgumentNullException("key");

                TValue item;
                if (Dictionary.TryGetValue(key, out item))
                {
                    if (add) throw new ArgumentException("An item with the same key has already been added.");
                    if (Equals(item, value)) return;
                    Dictionary[key] = value;

                    OnCollectionChanged(NotifyCollectionChangedAction.Replace, new KeyValuePair<TKey, TValue>(key, value), new KeyValuePair<TKey, TValue>(key, item), GetIndex(Dictionary, key));
                }
                else
                {
                    Dictionary[key] = value;

                    OnCollectionChanged(NotifyCollectionChangedAction.Add, new KeyValuePair<TKey, TValue>(key, value), GetIndex(Dictionary, key));
                }
            }

            private void OnPropertyChanged()
            {
                OnPropertyChanged(CountString);
                OnPropertyChanged(IndexerName);
                OnPropertyChanged(KeysName);
                OnPropertyChanged(ValuesName);
            }

            private int GetIndex(IDictionary<TKey, TValue> Dictionary, TKey key)
            {
                int i = 0;
                foreach (var dictKey in Dictionary.Keys)
                {
                    if (dictKey.Equals(key)) return i;
                }

                return -1;
            }

            protected virtual void OnPropertyChanged(string propertyName)
            {
                if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }

            private void OnCollectionChanged()
            {
                OnPropertyChanged();
                if (CollectionChanged != null) CollectionChanged(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
            }

            private void OnCollectionChanged(NotifyCollectionChangedAction action, KeyValuePair<TKey, TValue> changedItem, int index)
            {
                OnPropertyChanged();
                if (CollectionChanged != null) CollectionChanged(this, new NotifyCollectionChangedEventArgs(action, changedItem, index));
            }

            private void OnCollectionChanged(NotifyCollectionChangedAction action, KeyValuePair<TKey, TValue> newItem, KeyValuePair<TKey, TValue> oldItem, int index)
            {
                OnPropertyChanged();
                if (CollectionChanged != null) CollectionChanged(this, new NotifyCollectionChangedEventArgs(action, newItem, oldItem, index));
            }

            private void OnCollectionChanged(NotifyCollectionChangedAction action, IList newItems, int index)
            {
                OnPropertyChanged();
                if (CollectionChanged != null) CollectionChanged(this, new NotifyCollectionChangedEventArgs(action, newItems, index));
            }

            public override string ToString()
            {
                return string.Format("ObservableDictionary<{0}> Count={1}", GetKeyAndValue(Dictionary.GetType().GetGenericArguments()), Count);
            }

            private object GetKeyAndValue(Type[] Types)
            {
                string result = string.Empty;

                foreach (Type type in Types)
                {
                    result += type.ToString() + ",";
                }

                if (!string.IsNullOrEmpty(result) && result.Length > 1)
                    result = result.Substring(0, result.Length - 1);

                return result;
            }
        }
}

Give it a go and let me know how it works.