c#简单判断是否是闰年的方法代码

/// <summary>
        /// 判断是否闰年？
        /// </summary>
        /// <param name="a_year"></param>
        /// <returns></returns>
        public static bool isleapyear(int a_year)
        {
            string s;
            datetime dt;
            try
            {
                s = (a_year.tostring() + "-02-29");
                dt = convert.todatetime(s);
                return true;
            }
            catch
            {
                return false;
            }
        }