定义：将一个类的接口转换为另外一个用户所期望的接口。

Adapter设计模式允许一些类可以共同运行，这些类因为具有不兼容的接口而不能使用其它的方法。

UML：

示例：

View Code 
  1 // Adapter pattern -- Structural example 
  2 
  3 
  4 using System;
  5  
  6  
  7 namespace DoFactory.GangOfFour.Adapter.Structural
  8  
  9 {
 10  
 11   /// <summary>
 12  
 13 /// MainApp startup class for Structural
 14  
 15 /// Adapter Design Pattern.
 16  
 17 /// </summary>
 18  
 19   class MainApp
 20  
 21   {
 22  
 23     /// <summary>
 24  
 25 /// Entry point into console application.
 26  
 27 /// </summary>
 28  
 29     static void Main()
 30  
 31     {
 32  
 33       // Create adapter and place a request
 34  
 35       Target target = new Adapter();
 36  
 37       target.Request();
 38  
 39  
 40  
 41       // Wait for user
 42  
 43       Console.ReadKey();
 44  
 45     }
 46  
 47   }
 48  
 49  
 50  
 51   /// <summary>
 52  
 53 /// The 'Target' class
 54  
 55 /// </summary>
 56  
 57   class Target
 58  
 59   {
 60  
 61     public virtual void Request()
 62  
 63     {
 64  
 65       Console.WriteLine("Called Target Request()");
 66  
 67     }
 68  
 69   }
 70  
 71  
 72  
 73   /// <summary>
 74  
 75 /// The 'Adapter' class
 76  
 77 /// </summary>
 78  
 79   class Adapter : Target
 80  
 81   {
 82  
 83     private Adaptee _adaptee = new Adaptee();
 84  
 85  
 86  
 87     public override void Request()
 88  
 89     {
 90  
 91       // Possibly do some other work
 92  
 93 //  and then call SpecificRequest
 94  
 95       _adaptee.SpecificRequest();
 96  
 97     }
 98  
 99   }
100  
101  
102  
103   /// <summary>
104  
105 /// The 'Adaptee' class
106  
107 /// </summary>
108  
109   class Adaptee
110  
111   {
112  
113     public void SpecificRequest()
114  
115     {
116  
117       Console.WriteLine("Called SpecificRequest()");
118  
119     }
120  
121   }
122  
123 }
124

输出：

Called SpecificRequest()

View Code 
  1 // Adapter pattern -- Real World example 
  2 
  3 
  4 using System;
  5  
  6 
  7 namespace DoFactory.GangOfFour.Adapter.RealWorld
  8  
  9 {
 10  
 11   /// <summary>
 12  
 13 /// MainApp startup class for Real-World 
 14 
 15 /// Adapter Design Pattern.
 16  
 17 /// </summary>
 18  
 19   class MainApp
 20  
 21   {
 22  
 23     /// <summary>
 24  
 25 /// Entry point into console application.
 26  
 27 /// </summary>
 28  
 29     static void Main()
 30  
 31     {
 32  
 33       // Non-adapted chemical compound
 34  
 35       Compound unknown = new Compound("Unknown");
 36  
 37       unknown.Display();
 38  
 39  
 40  
 41       // Adapted chemical compounds
 42  
 43       Compound water = new RichCompound("Water");
 44  
 45       water.Display();
 46  
 47  
 48  
 49       Compound benzene = new RichCompound("Benzene");
 50  
 51       benzene.Display();
 52  
 53  
 54  
 55       Compound ethanol = new RichCompound("Ethanol");
 56  
 57       ethanol.Display();
 58  
 59  
 60  
 61       // Wait for user
 62  
 63       Console.ReadKey();
 64  
 65     }
 66  
 67   }
 68  
 69  
 70  
 71   /// <summary>
 72  
 73 /// The 'Target' class
 74  
 75 /// </summary>
 76  
 77   class Compound
 78  
 79   {
 80  
 81     protected string _chemical;
 82  
 83     protected float _boilingPoint;
 84  
 85     protected float _meltingPoint;
 86  
 87     protected double _molecularWeight;
 88  
 89     protected string _molecularFormula;
 90  
 91  
 92  
 93     // Constructor
 94  
 95     public Compound(string chemical)
 96  
 97     {
 98  
 99       this._chemical = chemical;
100  
101     }
102  
103  
104  
105     public virtual void Display()
106  
107     {
108  
109       Console.WriteLine("\nCompound: {0} ------ ", _chemical);
110  
111     }
112  
113   }
114  
115  
116  
117   /// <summary>
118  
119 /// The 'Adapter' class
120  
121 /// </summary>
122  
123   class RichCompound : Compound
124  
125   {
126  
127     private ChemicalDatabank _bank;
128  
129  
130  
131     // Constructor
132  
133     public RichCompound(string name)
134  
135       : base(name)
136  
137     {
138  
139     }
140  
141  
142  
143     public override void Display()
144  
145     {
146  
147       // The Adaptee
148  
149       _bank = new ChemicalDatabank();
150  
151  
152  
153       _boilingPoint = _bank.GetCriticalPoint(_chemical, "B");
154  
155       _meltingPoint = _bank.GetCriticalPoint(_chemical, "M");
156  
157       _molecularWeight = _bank.GetMolecularWeight(_chemical);
158  
159       _molecularFormula = _bank.GetMolecularStructure(_chemical);
160  
161  
162  
163       base.Display();
164  
165       Console.WriteLine(" Formula: {0}", _molecularFormula);
166  
167       Console.WriteLine(" Weight : {0}", _molecularWeight);
168  
169       Console.WriteLine(" Melting Pt: {0}", _meltingPoint);
170  
171       Console.WriteLine(" Boiling Pt: {0}", _boilingPoint);
172  
173     }
174  
175   }
176  
177  
178  
179   /// <summary>
180  
181 /// The 'Adaptee' class
182  
183 /// </summary>
184  
185   class ChemicalDatabank
186  
187   {
188  
189     // The databank 'legacy API'
190  
191     public float GetCriticalPoint(string compound, string point)
192  
193     {
194  
195       // Melting Point
196  
197       if (point == "M")
198  
199       {
200  
201         switch (compound.ToLower())
202  
203         {
204  
205           case "water": return 0.0f;
206  
207           case "benzene": return 5.5f;
208  
209           case "ethanol": return -114.1f;
210  
211           default: return 0f;
212  
213         }
214  
215       }
216  
217       // Boiling Point
218  
219       else
220  
221       {
222  
223         switch (compound.ToLower())
224  
225         {
226  
227           case "water": return 100.0f;
228  
229           case "benzene": return 80.1f;
230  
231           case "ethanol": return 78.3f;
232  
233           default: return 0f;
234  
235         }
236  
237       }
238  
239     }
240  
241  
242  
243     public string GetMolecularStructure(string compound)
244  
245     {
246  
247       switch (compound.ToLower())
248  
249       {
250  
251         case "water": return "H20";
252  
253         case "benzene": return "C6H6";
254  
255         case "ethanol": return "C2H5OH";
256  
257         default: return "";
258  
259       }
260  
261     }
262  
263  
264  
265     public double GetMolecularWeight(string compound)
266  
267     {
268  
269       switch (compound.ToLower())
270  
271       {
272  
273         case "water": return 18.015;
274  
275         case "benzene": return 78.1134;
276  
277         case "ethanol": return 46.0688;
278  
279         default: return 0d;
280  
281       }
282  
283     }
284  
285   }
286  
287 }
288

输出：

Compound: Unknown ------
Compound: Water ------ Formula: H20 Weight : 18.015 Melting Pt: 0 Boiling Pt: 100
Compound: Benzene ------ Formula: C6H6 Weight : 78.1134 Melting Pt: 5.5 Boiling Pt: 80.1
Compound: Alcohol ------ Formula: C2H6O2 Weight : 46.0688 Melting Pt: -114.1 Boiling Pt: 78.3