C#, Lesson 12 of "Xiaobai Learning Program": Calendar preparation, datetime calculation method and code

1 text format

/// <summary>
/// Lesson 12 of "Xiaobai Learning Program": Calendar preparation, time DateTime calculation method and code
/// This lesson learns the simple method of time type data DateTime, and compiles a month calendar.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button12_Click(object sender, EventArgs e)
{     // Set as the 1st of a certain month     DateTime day = DateTime.Parse("2025-08-01 10:10:00");     // Record the month     int month = day.Month;     // What day is the 1st? Equal to the number of spaces left before the 1st day of the calendar;     DayOfWeek weekday = day.DayOfWeek;     int wd = (int)weekday;

    StringBuilder sb = new StringBuilder();
    sb.AppendLine("<style>td { padding:5px;text-align:center;} </style>");
    sb.AppendLine("<table width=420 border=1 style='border-collapse:collapse;'>");

    // The first row of the calendar, header, actual Sunday, Monday, Tuesday. . . . . .
    sb.AppendLine("<tr style='background-color:#EEEEFF;'>");
    sb.AppendLine("<td>day</td>");
    sb.AppendLine("<td>one</td >");
    sb.AppendLine("<td>two</td>");
    sb.AppendLine("<td>three</td>");
    sb.AppendLine("<td>four</td>" );
    sb.AppendLine("<td>five</td>");
    sb.AppendLine("<td>six</td>");
    sb.AppendLine("</tr>");

    sb.AppendLine("<tr>");
    // If the 1st is not a Sunday, leave some spaces in front
    if (wd > 0)
    {         int nn = wd;         for (int i = 0; i < nn; i++)         {             sb. AppendLine("<td> </td>");         }     }

    // loop, the condition is that the month does not change!
    while (day.Month == month)
    {         // Print the date         sb.AppendLine("<td>" + day.Day + "</td>");         // If it is Sunday, wrap! ! !         if ((int)day.DayOfWeek == 6)         {             sb.AppendLine("</tr>");             sb.AppendLine("<tr>");         }         // add one day to the time         day = day.AddDays( 1);     }

    // The last day, if it is not Saturday, need to add a few spaces!
    int de = (int)day.DayOfWeek;
    for (int i = de; i < 6; i++)
    {         sb.AppendLine("<td> </td>");     }

    sb.AppendLine("</tr>");
    sb.AppendLine("</table>");

    webBrowser1.DocumentText = sb.ToString();
}
 

2 code format

/// <summary>
/// 《小白学程序》第十二课：日历的编制，时间DateTime的计算方法与代码
/// 本课学习时间类型的数据 DateTime 的简单方法，并编制一个月的日历。
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button12_Click(object sender, EventArgs e)
{
    // 设定为某个月的1号
    DateTime day = DateTime.Parse("2025-08-01 10:10:00");
    // 记录 月份
    int month = day.Month;
    // 1号 是星期几？ 等于日历1号前面留出的空格数；
    DayOfWeek weekday = day.DayOfWeek;
    int wd = (int)weekday;

    StringBuilder sb = new StringBuilder();
    sb.AppendLine("<style>td { padding:5px;text-align:center;} </style>");
    sb.AppendLine("<table width=420 border=1 style='border-collapse:collapse;'>");

    // 日历第一行，表头，现实星期日、一、二、。。。。。。
    sb.AppendLine("<tr style='background-color:#EEEEFF;'>");
    sb.AppendLine("<td>日</td>");
    sb.AppendLine("<td>一</td>");
    sb.AppendLine("<td>二</td>");
    sb.AppendLine("<td>三</td>");
    sb.AppendLine("<td>四</td>");
    sb.AppendLine("<td>五</td>");
    sb.AppendLine("<td>六</td>");
    sb.AppendLine("</tr>");

    sb.AppendLine("<tr>");
    // 如果 1号不是周日，前面留出一些空格
    if (wd > 0)
    {
        int nn = wd;
        for (int i = 0; i < nn; i++)
        {
            sb.AppendLine("<td> </td>");
        }
    }

    // 循环，条件是 月份 不变！
    while (day.Month == month)
    {
        // 打印日期
        sb.AppendLine("<td>" + day.Day + "</td>");
        // 如果是周日，换行！！！
        if ((int)day.DayOfWeek == 6)
        {
            sb.AppendLine("</tr>");
            sb.AppendLine("<tr>");
        }
        // 时间往后面加一天
        day = day.AddDays(1);
    }

    // 最后一天，如果不是周六，需要增加几个空格！
    int de = (int)day.DayOfWeek;
    for (int i = de; i < 6; i++)
    {
        sb.AppendLine("<td> </td>");
    }

    sb.AppendLine("</tr>");
    sb.AppendLine("</table>");

    webBrowser1.DocumentText = sb.ToString();
}