WPF字典集合类ObservableDictionary

WPF最核心的技术优势之一就是数据绑定。数据绑定，可以通过对数据的操作来更新界面。

数据绑定最经常用到的是ObservableCollection<T> 和 Dictionary<T, T> 这两个类。

ObservableCollection表示一个动态数据集合，在添加项、移除项或刷新整个列表时，此集合将提供通知，可以通过更新集合数据来更新界面显示。

Dictionary字典类，检索和数据操作性能极性，所以一些配置项的集合都使用它来保存。

因此，大家就想到的，有没有ObservableCollection和Dictionary相结合的类呢，于是就形成的ObservableDictionary类。

网上有很多版本的ObservableDictionary类，据我了解到的，最早且最经典的就是Dr.WPF里面的ItemsControl to a dictionary，其他的版本多数是参考这个来修改的（不对的那就是我孤陋寡闻了）。

今天我提供的这个版本，也是参考了网上的其他版本和Dr.WPF里的。

Dr.WPF里的定义是这样的：

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public class ObservableDictionary <TKey, TValue> :         IDictionary<TKey, TValue>,         ICollection<KeyValuePair<TKey, TValue>>,         IEnumerable<KeyValuePair<TKey, TValue>>,         IDictionary,         ICollection,         IEnumerable,         ISerializable,         IDeserializationCallback,         INotifyCollectionChanged,         INotifyPropertyChanged

大家细心点就会发现，这里继承的接口和Dictionary<TKey, TValue>所继承的大部分相同，只是多了INotifyCollectionChanged, INotifyPropertyChanged

于是，今天我提供的版本，就直接继承于Dictionary<TKey, TValue>和INotifyCollectionChanged, INotifyPropertyChanged。

本人测试过，无BUG，性能也极佳，下面上代码:

+ View Code?

public class ObservableDictionary<TKey, TValue> : Dictionary<TKey, TValue>, INotifyCollectionChanged, INotifyPropertyChanged

{

    public ObservableDictionary()

        : base()

    { }

 

    private int _index;

    public event NotifyCollectionChangedEventHandler CollectionChanged;

    public event PropertyChangedEventHandler PropertyChanged;

 

    public new KeyCollection Keys

    {

        get { return base.Keys; }

    }

 

    public new ValueCollection Values

    {

        get { return base.Values; }

    }

 

    public new int Count

    {

        get { return base.Count; }

    }

 

    public new TValue this[TKey key]

    {

        get { return this.GetValue(key); }

        set { this.SetValue(key, value); }

    }

 

    public TValue this[int index]

    {

        get { return this.GetIndexValue(index); }

        set { this.SetIndexValue(index, value); }

    }

 

    public new void Add(TKey key, TValue value)

    {

        base.Add(key, value);

        this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, this.FindPair(key), _index));

        OnPropertyChanged("Keys");

        OnPropertyChanged("Values");

        OnPropertyChanged("Count");

    }

 

    public new void Clear()

    {

        base.Clear();

        this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));

        OnPropertyChanged("Keys");

        OnPropertyChanged("Values");

        OnPropertyChanged("Count");

    }

 

    public new bool Remove(TKey key)

    {

        var pair = this.FindPair(key);

        if (base.Remove(key))

        {

            this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, pair, _index));

            OnPropertyChanged("Keys");

            OnPropertyChanged("Values");

            OnPropertyChanged("Count");

            return true;

        }

        return false;

    }

 

    protected void OnCollectionChanged(NotifyCollectionChangedEventArgs e)

    {

        if (this.CollectionChanged != null)

        {

            this.CollectionChanged(this, e);

        }

    }

 

    protected void OnPropertyChanged(string propertyName)

    {

        if (this.PropertyChanged != null)

        {

            this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));

        }

    }

 

    #region private方法

    private TValue GetIndexValue(int index)

    {

        for (int i = 0; i < this.Count; i++)

        {

            if (i == index)

            {

                var pair = this.ElementAt(i);

                return pair.Value;

            }

        }

 

        return default(TValue);

    }

 

    private void SetIndexValue(int index, TValue value)

    {

        try

        {

            var pair = this.ElementAtOrDefault(index);

            SetValue(pair.Key, value);               

        }

        catch (Exception)

        {

             

        }

    }

 

    private TValue GetValue(TKey key)

    {

        if (base.ContainsKey(key))

        {

            return base[key];

        }

        else

        {

            return default(TValue);

        }

    }

 

    private void SetValue(TKey key, TValue value)

    {

        if (base.ContainsKey(key))

        {

            var pair = this.FindPair(key);

            int index = _index;

            base[key] = value;

            var newpair = this.FindPair(key);

            this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, newpair, pair, index));

            OnPropertyChanged("Values");

            OnPropertyChanged("Item[]");

        }

        else

        {

            this.Add(key, value);

        }

    }

 

    private KeyValuePair<TKey, TValue> FindPair(TKey key)

    {

        _index = 0;

        foreach (var item in this)

        {

            if (item.Key.Equals(key))

            {

                return item;

            }

            _index++;

        }

        return default(KeyValuePair<TKey, TValue>);

    }

 

    private int IndexOf(TKey key)

    {

        int index = 0;

        foreach (var item in this)

        {

            if (item.Key.Equals(key))

            {

                return index;

            }

            index++;

 

        }

        return -1;

    }

 

    #endregion

 

}

扩展方面，大家可以以Dr.WPF版本来修改，那个更加有技术含量和可扩展性更强！