/// <summary>
/// 下级地区等级
/// </summary>
/// <param name="value">地区等级</param>
/// <param name="result">下级地区等级</param>
public static bool TryLowerLevel(this AreaLevel value, out AreaLevel?result)
{
if (value == AreaLevel.Town)
{
result = null;
return(false);
}
result = value.LowerLevel();
return(true);
}
