public void Save(ControllerContext context, ITempDataProvider provider)
{
Precondition.Require(context, () => Error.ArgumentNull("context"));
Precondition.Require(provider, () => Error.ArgumentNull("provider"));
string[] keysToKeep = _initialKeys.Union(_retainedKeys, StringComparer.OrdinalIgnoreCase).ToArray();
string[] keysToRemove = _data.Keys.Except(keysToKeep, StringComparer.OrdinalIgnoreCase).ToArray();
foreach (string key in keysToRemove)
{
_data.Remove(key);
}
provider.Save(context, _data);
}