Convert datetime?

i try to write some code:

Firstly there is a textbox. if you write 13 in textbox, it equals 13.02.2009 (datetime)

Secondly if datetime.now equals 15.02.2009 , you write 13 in textbox, a function return 13.03.2009.

Help me thanks...

From stackoverflow

• For the second time: go get a book.

  DateTime whichday(int day)
  {
   DateTime today = DateTime.Today;
  
   if(today.Day > day)
    return new DateTime(today.Year, today.Month, day).AddMonth(1);
  
   return new DateTime(today.Year, today.Month, day);
  }
  

  Rowland Shaw : what if the day is 29 (in February)?

  Gerrie Schenck : You can't use AddMonth... ykaratoprak don't want to use math (check his comment) :)

  Phsika : Gerrie Schenck you don2t understand well. i f i say math, i don't like +,-,% , so you can C# special property like addmounth

• public static DateTime GetDate(int day)
  {
      int month = 0;
      if (day >= DateTime.Now.Day) {month = DateTime.Now.Month;}
      else {month = (DateTime.Now.AddMonths(1).Month);}
      DateTime date = new DateTime(DateTime.Now.Year, month, day);
      return date;
  }
  

  Anton Gogolev : What if DateTime.Now.Month == 12?

  Canavar : yeap, you're right

• Please try this code and what I mean. Thanks ScarletGarden. Maybe Natrium will learn something about my level.

   static void Main(string[] args)
          {
  
    DateTime startdate=Convert.ToDateTime("15.02.2009");
              int[] frequency ={ 16 }; 
  
              startdate = startdate.AddDays(1 - startdate.Day)
                   .AddDays(frequency[0] -  1)
                   .AddMonths((startdate.Day > frequency[0]) ?1:0);
              Console.Write(startdate.ToString());
              Console.ReadKey();}
  

  For month 15th result is 16.02.2009 but for month 11th result is 11.03.2009 because frequency[0] > startdate is outofdate.