using System;

public class Program

{

    public static void Main()

    {

        var t = new TimePeriod();

        t.Hours = 30;

    }

}

class TimePeriod

{

   private double _seconds;

​

   public double Hours

   {

       get { return _seconds / 3600; }

       set { 

          if (value < 0 || value > 24)

             throw new ArgumentOutOfRangeException("Hours must be between 0 and 24.");

​

          _seconds = value * 3600; 

       }

   }

}