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IPointy[] myPointObjs = { new Hexagon(), new Knife(), new Triangle() }; foreach (var i in myPointObjs){ Console.WriteLine(i.Points); } |
full example
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using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Interace { class Program { static IPointy FindFirstPointyShape(Shape[] shapes) { foreach (var s in shapes) { if (s is IPointy) { return s as IPointy; } } return null; } static void Main(string[] args) { IPointy[] myPointObjs = { new Hexagon(), new Knife(), new Triangle() }; foreach (var i in myPointObjs){ Console.WriteLine(i.Points); } Shape[] shapes = { new Triangle("Triangle"), new Hexagon("Hexagon"), new Circle("Circle") }; IPointy firstPointyItem = FindFirstPointyShape(shapes); Console.WriteLine("Item has {0} points", firstPointyItem.Points); Triangle t = new Triangle("Triangle"); t.Draw(); Hexagon h = new Hexagon("Hexagon"); h.Draw(); Circle c = new Circle("Circle"); c.Draw(); // another example for (int i = 0; i < shapes.Length; i++) { if (shapes[i] is IPointy) Console.WriteLine("Points in " + shapes[i].Name + " " + (shapes[i] as IPointy).Points); else Console.WriteLine("Ipointy not supported in " + shapes[i].Name); } Circle c1 = new Circle("Circle"); IPointy itf = null; try { itf = (IPointy)c1; } catch (InvalidCastException e) { Console.WriteLine(e.Message); } Console.ReadLine(); } // base class public class Shape { public string Name { get; set; } public Shape(string name) { Name = name; } public Shape() { } public virtual void Draw() { } } //declaring interface public interface IPointy { byte Points { get; } } // another one public interface IDraw3D { void Draw3D(); } // Triangle - derived from shape and implementing IPointy public class Triangle : Shape, IPointy { public Triangle() { } public Triangle(string name) : base(name) { } public override void Draw() { Console.WriteLine("Shape name is {0}", this.Name); } public byte Points { get { return 3; } } } // Hexagon - derived from shape and implementing IPointy public class Hexagon : Shape, IPointy, IDraw3D { public Hexagon() { } public Hexagon(string name) : base(name) { } public override void Draw() { Console.WriteLine("Shape name is {0}", this.Name); } public byte Points { get { return 6; } } // << another implementation of IPointy public void Draw3D() { Console.WriteLine("Drawing Hexagon in 3D"); } } // // Circle - derived from shape and NOT implementing IPointy public class Circle : Shape { public Circle() { } public Circle(string name) : base(name) { } public override void Draw() { Console.WriteLine("Shape name is {0}", this.Name); } } public class ThreeDCircle : Circle, IDraw3D { public void Draw3D() { Console.WriteLine("Draw Circle in 3D"); } } // knife public class Knife : Shape, IPointy { public Knife() { } public Knife(string name) : base(name) { } public override void Draw() { Console.WriteLine("Shape name is {0}", this.Name); } public byte Points { get { return 4; } } // << another implementation of IPointy } // fork public class Fork : Shape, IPointy { public Fork() { } public Fork(string name) : base(name) { } public override void Draw() { Console.WriteLine("Shape name is {0}", this.Name); } public byte Points { get { return 1; } } // << another implementation of IPointy } } } |