Prototype Pattern C# with Example



Prototype Pattern C# with Example

Specify the kind of objects to create using a prototypical instance, and create new objects by copying this prototype. 
In this example demonstrates the Prototype pattern in which new Color objects are created by copying pre-existing, 
user-defined Colors of the same type. 
using System; 
using System.Collections.Generic; 
namespace GangOfFour.Prototype 
{ 
///  
/// MainApp startup class for Real-World 
/// Prototype Design Pattern. 
///  
class MainApp 
{ 
///  
 

/// Entry point into console application. 
///  
static void Main() 
{ 
ColorManager colormanager = new ColorManager(); 
// Initialize with standard colors 
colormanager["red"] = new Color(255, 0, 0); 
colormanager["green"] = new Color(0, 255, 0); 
colormanager["blue"] = new Color(0, 0, 255); 
// User adds personalized colors 
colormanager["angry"] = new Color(255, 54, 0); 
colormanager["peace"] = new Color(128, 211, 128); 
colormanager["flame"] = new Color(211, 34, 20); 
// User clones selected colors 
Color color1 = colormanager["red"].Clone() as Color; 
Color color2 = colormanager["peace"].Clone() as Color; 
Color color3 = colormanager["flame"].Clone() as Color; 
// Wait for user 
Console.ReadKey(); 
} 
} 
///  
/// The 'Prototype' abstract class 
///  
abstract class ColorPrototype 
{ 
public abstract ColorPrototype Clone(); 
} 
///  
///  The  'ConcretePrototype'  class 
///  
class Color : ColorPrototype 
{ 
private int _red; 
private int _green; 
private int _blue; 
// Constructor 
public Color(int red, int green, int blue) 
{ 
this._red = red; 
this._green = green; 
this._blue = blue; 
} 
// Create a shallow copy 
public override ColorPrototype Clone() 
{ 
Console.WriteLine( 
"Cloning color RGB: {0,3},{1,3},{2,3}", 
_red, _green, _blue); 
return this.MemberwiseClone() as ColorPrototype; 
} 
} 
 

///  
/// Prototype manager 
///  
class ColorManager 
{ 
private Dictionary _colors = 
new Dictionary(); 
// Indexer 
public ColorPrototype this[string key] 
{ 
get { return _colors[key]; } 
set { _colors.Add(key, value); } 
} 
} 
} 
Output: 
Cloning color RGB: 255, 0, 0 
Cloning color RGB: 128,211,128 
Cloning color RGB: 211, 34, 20 
 

Design Pattern 

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