public override void RemoveAt(string parameterName)
{
NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "RemoveAt", parameterName);
int index = IndexOf(parameterName);
NpgsqlParameter existing = InternalList[index];
this.InternalList.RemoveAt(index);
existing.Collection = null;
this.InvalidateHashLookups();
}