原文：http://hi.baidu.com/wosxiaoyao/item/1837b791fde008d57b7f014f

其中的输出日历类Calendar如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace xianshirili
{
    public class Calendar
    {
        public void PrintCalendar(int year, int month,TextBox textbox)
        {
            StringBuilder builder = new StringBuilder();
            builder.Append(" 日 一 二 三 四 五 六\r\n");
            int hawdays = GetWeeksOfDate(year, month, 1); //这个月的第一天星期几
            int days = GetDaysOfMonth(year, month); //获取想要输出月份的天数
           
            for (int i = 1; i <= hawdays * 3; i++) //打印第一排前面的空格
            {
                builder.Append(" ");
            }
            for (int j = 1; j <= days; j++)
            {

                if (j <= 9)
                {
                    builder.Append(" ");
                    builder.Append(" ");
                    builder.Append(Convert.ToString(j));
                }
                // Console.Write(" {0}", j);

                if (j >= 10)
                {
                    builder.Append(" ");
                    builder.Append(Convert.ToString(j));
                }
                // Console.Write(" {0}", j);
                if ((hawdays + j) % 7 == 0)
                    builder.Append("\r\n");
            }
           
            textbox.Text = builder.ToString();
        }

        // 计算当前日期以前的天数
        public static int GetDaysOfDate(int year, int month, int day)
        {
            int days = 0;
            for (int i = 1980; i < year; i++)
            {
                days += GetDaysOfYears(i);
            }
            for (int i = 1; i < month; i++)
            {
                days += GetDaysOfMonth(year, i);

            }
            days = days + day - 1;
            return days;
        }

        //计算星期，返回具体的某一天星期几 值为0~6
        public static int GetWeeksOfDate(int year, int month, int day)
        {
            int weeks = GetDaysOfDate(year, month, day);

            return (weeks + 2) % 7;
        }

        // 判断是否闰年并返回当年总天数
        public static bool LeapYear(int year)
        {
            return ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
        }

        //判断月份，返回当月的天数
        public static int GetDaysOfMonth(int year, int month)
        {
            int days = 30;
            switch (month)
            {
                case 1:
                case 3:
                case 5:
                case 7:
                case 8:
                case 10:
                case 12:
                    days = 31; break;
                case 4:
                case 6:
                case 9:
                case 11:
                    days = 30; break;
                case 2:
                    days = LeapYear(year) ? 29 : 28; break;
                default:
                    days = 30; break;
            }
            return days;
        }

        //根据年，判断是否闰年并返回一年里有几天
        public static int GetDaysOfYears(int year)
        {
            return LeapYear(year) ? 366 : 365;
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;

public class Calendar
{
    public void PrintCalendar(int year, int month, TextBox textbox)
    {
        StringBuilder builder = new StringBuilder();
        builder.Append(" 日 一 二 三 四 五 六\r\n");
        int hawdays = GetWeeksOfDate(year, month, 1); //这个月的第一天星期几
        int days = GetDaysOfMonth(year, month); //获取想要输出月份的天数

        for (int i = 1; i <= hawdays * 3; i++) //打印第一排前面的空格
        {
            builder.Append(" ");
        }
        for (int j = 1; j <= days; j++)
        {