Indexer for generic type : Indexer « Class « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Class
3. Indexer

using System.Collections;

public abstract class Shape
{
   public abstract void Draw();
}

public class Rectangle : Shape
{
   public override void Draw()
   {
      System.Console.WriteLine( "Rectangle.Draw" );
   }
}

public class Circle : Shape
{
   public override void Draw()
   {
      System.Console.WriteLine( "Circle.Draw" );
   }
}

public class ShapeList
{
   private ArrayList shapes;

   public ShapeList()
   {
      shapes = new ArrayList();
   }

   public int Count
   {
      get
      {
         return shapes.Count;
      }
   }

   public Shape this[ int index ]
   {
      get
      {
         return (Shape) shapes[index];
      }
   }

   public void Add( Shape shape )
   {
      shapes.Add( shape );
   }
}

public class MainClass
{
   static void Main()
   {
      ShapeList drawing = new ShapeList();

      drawing.Add( new Rectangle() );
      drawing.Add( new Circle() );
      
      for( int i = 0; i < drawing.Count; ++i ) {
         Shape shape = drawing[i];
         shape.Draw();
      }
   }
}

Rectangle.Draw
Circle.Draw