internal override void PrepareSave(ConfigurationElement parentElement, ConfigurationSaveMode mode)
{
var parent = (ConfigurationElementCollection)parentElement;
base.PrepareSave(parentElement, mode);
for (int n = 0; n < list.Count; n++)
{
ConfigurationElement elem = (ConfigurationElement)list [n];
object key = GetElementKey(elem);
ConfigurationElement pitem = parent != null?parent.BaseGet(key) as ConfigurationElement : null;
elem.PrepareSave(pitem, mode);
}
}