public IDependencyValueStorage this[DependencyValueStorageKey key]
{
get
{
IDependencyValueStorage storage;
if (_storages.TryGetValue(key, out storage))
{
return(storage);
}
return(null);
}
set
{
if (key == DefaultKey)
{
throw new InvalidOperationException("Default storage is readonly.");
}
IDependencyValueStorage storage;
if (_storages.TryGetValue(key, out storage))
{
if (storage != value)
{
storage.CurrentValueChanged -= Storage_CurrentValueChanged;
if (value != null)
{
UpdateStorage(key, storage, value);
value.CurrentValueChanged += Storage_CurrentValueChanged;
}
else
{
RemoveStorage(key, storage);
}
}
}
else
{
if (value != null)
{
AddStorage(key, value);
value.CurrentValueChanged += Storage_CurrentValueChanged;
}
}
}
}
private void UpdateStorage(DependencyValueStorageKey key, IDependencyValueStorage old, IDependencyValueStorage value)
{
var dps = value.Keys.Union(old.Keys).ToList();
UpdateStorage(dps, () => _storages[key] = value);
}
private void RemoveStorage(DependencyValueStorageKey key, IDependencyValueStorage storage)
{
var dps = storage.Keys.ToList();
UpdateStorage(dps, () => _storages.Remove(key));
}
private void AddStorage(DependencyValueStorageKey key, IDependencyValueStorage storage)
{
var dps = storage.Keys.ToList();
UpdateStorage(dps, () => _storages.Add(key, storage));
}