Is there an IDictionary implementation that, on missing key, returns the default value instead of throwing?

Question

The indexer into Dictionary throws an exception if the key is missing. Is there an implementation of IDictionary that instead will return de

Answer 1

public class DefaultIndexerDictionary : IDictionary
{
    private IDictionary _dict = new Dictionary();

    public TValue this[TKey key]
    {
        get
        {
            TValue val;
            if (!TryGetValue(key, out val))
                return default(TValue);
            return val;
        }

        set { _dict[key] = value; }
    }

    public ICollection Keys => _dict.Keys;

    public ICollection Values => _dict.Values;

    public int Count => _dict.Count;

    public bool IsReadOnly => _dict.IsReadOnly;

    public void Add(TKey key, TValue value)
    {
        _dict.Add(key, value);
    }

    public void Add(KeyValuePair item)
    {
        _dict.Add(item);
    }

    public void Clear()
    {
        _dict.Clear();
    }

    public bool Contains(KeyValuePair item)
    {
        return _dict.Contains(item);
    }

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

    public void CopyTo(KeyValuePair[] array, int arrayIndex)
    {
        _dict.CopyTo(array, arrayIndex);
    }

    public IEnumerator> GetEnumerator()
    {
        return _dict.GetEnumerator();
    }

    public bool Remove(TKey key)
    {
        return _dict.Remove(key);
    }

    public bool Remove(KeyValuePair item)
    {
        return _dict.Remove(item);
    }

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

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