Demonstrating extension methods.

Description

Demo Code



using System; // for class ArgumentOutOfRangeException

public class Time2
{
   private int hour; // 0 - 23
   private int minute; // 0 - 59
   private int second; // 0 - 59

   // constructor can be called with zero, one, two or three arguments
   public Time2(int hour = 0, int minute = 0, int second = 0)
   {//w w  w .jav  a 2 s . c o m
      SetTime(hour, minute, second); // invoke SetTime to validate time
   }

   // Time2 constructor: another Time2 object supplied as an argument
   public Time2(Time2 time)
      : this(time.Hour, time.Minute, time.Second) { }

   // set a new time value using universal time; ensure that
   // the data remains consistent by setting invalid values to zero
   public void SetTime(int hour, int minute, int second)
   {
      Hour = hour; // set the Hour property
      Minute = minute; // set the Minute property
      Second = second; // set the Second property
   }

   // property that gets and sets the hour
   public int Hour
   {
      get
      {
         return hour;
      }
      set
      {
         if (value < 0 || value > 23)
         {
            throw new ArgumentOutOfRangeException(nameof(value),
               value, $"{nameof(Hour)} must be 0-23");
         }

         hour = value;
      }
   }

   // property that gets and sets the minute
   public int Minute
   {
      get
      {
         return minute;
      }
      set
      {
         if (value < 0 || value > 59)
         {
            throw new ArgumentOutOfRangeException(nameof(value),
               value, $"{nameof(Minute)} must be 0-59");
         }

         minute = value;
      }
   }

   // property that gets and sets the second
   public int Second
   {
      get
      {
         return second;
      }
      set
      {
         if (value < 0 || value > 59)
         {
            throw new ArgumentOutOfRangeException(nameof(value),
               value, $"{nameof(Second)} must be 0-59");
         }

         second = value;
      }
   }

   // convert to string in universal-time format (HH:MM:SS)
   public string ToUniversalString() =>
      $"{Hour:D2}:{Minute:D2}:{Second:D2}";

   // convert to string in standard-time format (H:MM:SS AM or PM)
   public override string ToString() =>
      $"{((Hour == 0 || Hour == 12) ? 12 : Hour % 12)}:" +
      $"{Minute:D2}:{Second:D2} {(Hour < 12 ? "AM" : "PM")}";
}

class MainClass
{
   static void Main()
   {
      var myTime = new Time2(); // call Time constructor
      myTime.SetTime(11, 34, 15); // set the time to 11:34:15

      // test the DisplayTime extension method
      Console.Write("Use the DisplayTime extension method: ");
      myTime.DisplayTime();

      // test the AddHours extension method
      Console.Write("Add 5 hours with the AddHours extension method: ");
      var timeAdded = myTime.AddHours(5); // add five hours
      timeAdded.DisplayTime(); // display the new Time2 object

      // add hours and display the time in one statement
      Console.Write("Add 15 hours with the AddHours extension method: ");
      myTime.AddHours(15).DisplayTime(); // add hours and display time

      // use fully qualified extension-method name to display the time
      Console.Write("Use fully qualified extension-method name: ");
      TimeExtensions.DisplayTime(myTime);
   }
}

// extension-methods class
static class TimeExtensions
{
   // display the Time2 object in console
   public static void DisplayTime(this Time2 aTime)
   {
      Console.WriteLine(aTime.ToString());
   }

   public static Time2 AddHours(this Time2 aTime, int hours)
   {
      // create a new Time object
      var newTime = new Time2() {
         Minute = aTime.Minute, Second = aTime.Second};

      // add the specified number of hours to the given time
      newTime.Hour = (aTime.Hour + hours) % 24;

      return newTime; // return the new Time2 object
   }
}
Demonstrating extension methods. - CSharp Custom Type

Description

Demo Code

Result

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