判断是否是闰年的方法

/// <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;
            }
        }