ASP.NET生成日历

public string GetDayList(DateTime? date)
{
    int day = 0;
    var minDate = Convert.ToDateTime(((DateTime)(date ?? DateTime.Now)).ToString("yyyy-MM-01"));
    var maxDate = minDate.AddMonths(1).AddDays(-1);

    var sb = new StringBuilder();

    sb.Append("<table>");
    sb.Append("<thead>");
    sb.Append("<tr>");
    sb.Append("<th>周日</th><th>周一</th><th>周二</th><th>周三</th><th>周四</th><th>周五</th><th>周六</th>");
    sb.Append("</tr>");
    sb.Append("</thead>");
    sb.Append("<tbody>");
    sb.Append("<tr>");
    while (true)
    {
        if (minDate > maxDate)
        {
            if (day > 6)
            {
                break;
            }
            else
            {
                sb.Append("<td></td>");
                day++;
                continue;
            }
        }

        if ((int)minDate.DayOfWeek == day)
        {
            sb.AppendFormat("<td>{0}</td>", minDate.Day);
            minDate = minDate.AddDays(1);
        }
        else
        {
            sb.Append("<td></td>");
        }

        if (day == 6)
        {
            sb.Append("</tr><tr>");
            day = -1;
        }

        day++;
    }
    sb.Append("</tr>");
    sb.Append("</tbody>");
    sb.Append("</table>");

    return sb.ToString();
}

加上CSS后效果图：