Gets the number of weeks in the current year

 /// <summary>
 ///  Get a few weeks of this year
 /// </summary>
 /// <param name="year"></param>
 /// <returns></returns>
  public int GetWeekOfYear(int year)
  {
       DateTime the_Date = new DateTime(year,1,1);// This year the first 1 day
        TimeSpan tt=the_Date.AddYears(1)-the_Date;// Figure out how many days are in the current year
        return tt.Days / 7 + 1; // Because there are only 366 Days and 365 Day divided by the 7 It has a remainder so it always has to be added 1 weeks
  }

Gets the number of days of the current month

1 species:

   DateTime dt = new DateTime(2007, 1, 1);
   // in .net Internal processing is subtracting +1 The next month gets the number of days of the current month ( And the way to do that is actually to figure out the difference ) For example, :
   // Is the current month 2007 years 1 month 1 day , through AddMonths Method to add 1 Months is 2007 years 2 month 1 day , in .net We're going to figure out how many days apart they are .
   // So we can use this method to figure out how many days are in the current month
    TimeSpan tt = dt.AddMonths(1) - dt;
   // DateTime dt = new DateTime(2007,1,31);  If the time is 2007,1,31 add 1 A: Not every month minus the current month , Here's the explanation :
   /* Like for you to do 1 A project, 2010-01-01 Made for you, 1 In a month, yes 2010-02-01 delivery
     now 2010-01-31 Number for you to do, is also a requirement 1 Finished in two months, was supposed to be in 2010-02-31 Delivered by No., but 2 On no 31 So the time of delivery becomes 2010-02-28 The no.
    AddMonths Just add 1 Three months */
    Response.Write(tt);

The second:

public static int year;
    public static int month;
    public static int days;
    protected void Button1_Click(object sender, EventArgs e)
    {
        year = DateTime.Now.Year;
        month = DateTime.Now.Month;
        // Gets the number of days of the current month
        switch (month)
        {
            case 1:
                days = 31;
                break;
            case 2:
                if (DateTime.IsLeapYear(year))
                {
                    // A leap year 2 Month for 29 day
                    days = 29;
                }
                else
                {
                    // Not leap years, 2 Month for 28 day
                    days = 28;
                }
                break;
            case 3:
                days = 31;
                break;
            case 4:
                days = 30;
                break;
            case 5:
                days = 31;
                break;
            case 6:
                days = 30;
                break;
            case 7:
                days = 31;
                break;
            case 8:
                days = 31;
                break;
            case 9:
                days = 30;
                break;
            case 10:
                days = 31;
                break;
            case 11:
                days = 30;
                break;
            case 12:
                days = 31;
                break;
        }
        TextBox1.Text = days.ToString();
    }

protected void Page_Load(object sender, EventArgs e)
        {
            int day=GetWeekDay(2010,11);
            if (day != 0)
            {
                Response.Write(day);
            }
        }
        public int GetWeekDay(int year,int month)
        {
            switch (month)
            {
                case 1:
                case 3:
                case 5:
                case 7:
                case 8:
                case 10:
                case 12:
                    return 31;

                case 2:
                    if (DateTime.IsLeapYear(year))
                        return 29;
                    else
                        return 28;

                case 4:
                case 6:
                case 9:
                case 11:
                    return 30;
                default:
                    return 0;    
            }