/// <summary>
/// This checks "deeply" for the specified item.
/// That is, it tried first to find it in the top-level dictionary,
/// then it checks each of the parents, then it checks defaults if they exist.
/// If a "shallow" check is required, call "Shallow().Contains()" instead.
/// </summary>
/// <param name="item">The KeyValuePair of interest.</param>
/// <returns>A boolean value indicating it the item was found.</returns>
public bool Contains(KeyValuePair <TKey, TValue> item)
{
lock (_syncRoot)
{
// if the item exists at the top level, then we're done
if (_localEntries.Contains(item))
{
return(true);
}
// it doesn't really matter in what order the parents are searched (we either find it or not)
if (Parents.Any(parent => (parent as ICollection <KeyValuePair <TKey, TValue> >).Contains(item)))
{
return(true);
}
// lastly we need to check Defaults
return(LocalDefaults != null && (LocalDefaults as ICollection <KeyValuePair <TKey, TValue> >).Contains(item));
}
}
