日後若有Painter class也想使用IShape的strategy，只要也實做IGrapher即可。

完整程式碼如下

1/**//*
2(C) OOMusou 2007 http://oomusou.cnblogs.com
3
4Filename　　: DP_StrategyPattern3_polymorphism_this.cs
5Compiler　　: Visual Studio 2005 / C# 2.0
6Description : Demo how to use Strategy Pattern with this by Generic
7Release　　 : 04/07/2007 1.0
8*/
9using System;
10
11interface IGrapher {
12　string getText();
13}
14
15interface IShape<T> {
16　void draw(T grapher);
17}
18
19class Grapher : IGrapher {
20　private IShape<Grapher> shape;
21
22　private string text;
23
24　public Grapher() { }
25　public Grapher(IShape<Grapher> shape) : this(shape, "Hello Shape!!") { }
26　public Grapher(IShape<Grapher> shape, string text) {
27　　this.shape = shape;
28　　this.text = text;
29　}
30
31　public void drawShape() {
32　　this.shape.draw(this);
33　}
34
35　public void setShape(IShape<Grapher> shape, string text) {
36　　this.text = text;
37　　this.shape = shape;
38　}
39
40　public string getText () {
41　　return this.text;
42　}
43}
44
45class Triangle<T> : IShape<T> where T : IGrapher {
46 public void draw(T grapher) {
47　 Console.WriteLine("Draw {0:s} in Triangle", grapher.getText());
48　}
49}
50
51class Circle<T> : IShape<T> where T : IGrapher{
52　public void draw(T grapher) {
53　　Console.WriteLine("Draw {0:s} in Circle", grapher.getText());
54　}
55}
56
57class Square<T> : IShape<T> where T : IGrapher {
58　public void draw(T grapher) {
59　　Console.WriteLine("Draw {0:s} in Square", grapher.getText());
60　}
61}
62
63class main {
64　public static void Main() {
65　　Grapher theGrapher = new Grapher(new Square<Grapher>());
66　　theGrapher.drawShape();
67
68　　theGrapher.setShape(new Circle<Grapher>(), "Hello C#!!");
69　　theGrapher.drawShape();
70　}
71}

執行結果

Draw Hello Shape!! in Square

Draw Hello C#!! in Circle

Conclusion