c# 日历实现

 

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;

public partial class tt : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            Response.Write(cld(DateTime.Now));
        }
    }
    private int dw(DayOfWeek dw)
    {
        int result = 0;
        switch (dw)
        {
            case DayOfWeek.Monday:
                result = 1;
                break;
            case DayOfWeek.Tuesday:
                result = 2;
                break;
            case DayOfWeek.Wednesday:
                result = 3;
                break;
            case DayOfWeek.Thursday:
                result = 4;
                break;
            case DayOfWeek.Friday:
                result = 5;
                break;
            case DayOfWeek.Saturday:
                result = 6;
                break;
            default:
                result = 0;
                break;
        }
        return result;
    }
    private string cld(DateTime dt)
    {
        StringBuilder sb = new StringBuilder();       
        try
        {           
            int day = dt.Day;//当天
           
            DateTime cdt = dt.AddDays(1 - dt.Day);//当月第一天
            int OneInWeek = dw(cdt.DayOfWeek);//当月第一天星期

            int Days = DateTime.DaysInMonth(dt.Year, dt.Month);//当月天数

            DateTime ndt = dt.AddDays(1 - dt.Day).AddMonths(1);//下个月
            int LastInWeek =  dw(ndt.DayOfWeek);//下个月第一天星期

            DateTime pdt = dt.AddMonths(-1);//上个月
            int PDays = DateTime.DaysInMonth(pdt.Year, pdt.Month);//上个月天数

            sb.Append("<table border='1'><tr><td>日</td><td>一</td><td>二</td><td>三</td><td>四</td><td>五</td><td>六</td></tr><tr>");
           
            for (int i = 0; i < OneInWeek; i++)
            {
                sb.Append("<td>");
                sb.Append("<font color='gray'>" + (PDays + i - OneInWeek + 1).ToString() + "</font>");
                sb.Append("</td>");
            }
            for (int i = 1; i <= Days; i++)
            {
                sb.Append("<td>");
                sb.Append(i == day ? "<font color='red'>" + i.ToString() + "</font>" : i.ToString());
                sb.Append("</td>");
                if ((i + OneInWeek) % 7 == 0)
                {
                    sb.Append("</tr><tr>");
                }
            }
            if (LastInWeek != 0)
            {
                for (int i = 1; i <= (7 - LastInWeek); i++)
                {
                    sb.Append("<td>");
                    sb.Append("<font color='gray'>" + i.ToString() + "</font>");
                    sb.Append("</td>");
                }
            }
            sb.Append("<tr></table>");
           
        }
        catch
        { }
        return sb.ToString();
    }
}