委托 （代码复习）

  1 namespace DelegateDemo
  2 {
  3     //声明委托
  4     public delegate void MyDel();
  5     //声明带参的委托
  6     public delegate void MyDelAdd(int num1, int num2);
  7     //声明带有返值的委托
  8     public delegate string MyDelStrUp(string s);
  9 
 10     //声明委托用于演示匿名方法
 11     public delegate string ProcessString(string s);
 12 
 13     class Program
 14     {
 15         static void Main(string[] args)
 16         {
 17             #region 委托演示
 18             TestDel t = new TestDel();
 19             
 20             #region 简单实例化委托与调用委托
 21             Console.WriteLine("-----以下是简单使用委托演示--------");
 22             //t.MyMethod();
 23             ///实例化委托,用一个方法来进行实例化
 24             ///该方法签名要与委托签名一致
 25             MyDel del = new MyDel(t.MyMethod);
 26            
 27             ///调用委托
 28             del();
 29 
 30             //C#2.0后可以这种方式实例化委托
 31             MyDel del4 = t.MyMethod;
 32             del4();
 33 
 34             //用静态方法进行实例化
 35             del4 = TestDel.MyStaticMethod;
 36             del4();
 37 
 38             //以下代码效果相同
 39            // MyDelAdd del2 = new MyDelAdd(t.MyMethod);
 40            //del2(10, 20);
 41             MyDelAdd del2 = t.MyMethod;
 42             del2(10, 20);
 43 
 44             //MyDel3 del3 = new MyDel3(t.MyMethod);
 45             //Console.WriteLine(del3("abc"));
 46             #endregion           
 47 
 48             #region 匿名方法实例化委托
 49             Console.WriteLine("-----以下是匿名方法演示--------");
 50             //用匿名方法实例化委托
 51             ProcessString p = delegate(string inputString) {
 52                 return inputString.ToUpper();
 53             };
 54             //通过委托调用匿名方法
 55             Console.WriteLine(p("aaaa"));
 56             #endregion
 57 
 58             #region 委托多播演示
 59 
 60             Console.WriteLine("-----以下是委托多播演示--------");
 61             MyDel mydel1 = t.MyMethod;
 62             MyDel mydel2 = t.MyMethod2;
 63             MyDel mydel3 = TestDel.MyMethod3;
 64             MyDel allMyDel = mydel1 + mydel2 + mydel3;
 65             allMyDel();
 66             Console.WriteLine("-----   allMyDel -= mydel3;多播演示--------");
 67             allMyDel -= mydel3;
 68             allMyDel();
 69 
 70             #endregion
 71           
 72             #region 委托作为参数演示
 73 
 74             Console.WriteLine("-------以下是委托作为参数演示------");
 75             MyDelStrUp paramMyDel3 = t.MyMethod;
 76             TestDel.MyParamMethod("aaa", paramMyDel3);
 77 
 78             #endregion
 79 
 80             #region 委托作为返回值
 81 
 82             Console.WriteLine("---以下是委托作为返回值演示------");
 83             ///returnMyDel指向t.MyReturnMethod()的返回值
 84             MyDelStrUp returnMyDel = t.MyReturnMethod();
 85             ///returnMyDel指向t.MyMethod
 86             //MyDel3 returnMyDel = t.MyMethod;
 87 
 88             Console.WriteLine(returnMyDel("sssssssssssss"));
 89 
 90             #endregion
 91          
 92             #endregion
 93 
 94             //MyReturnDelegateTest my = new MyReturnDelegateTest();
 95             //my.MyTest();
 96             MyParamDelegateTest myParam = new MyParamDelegateTest();
 97             myParam.AddBooks();
 98             myParam.MyTest();
 99             Console.Read();
100         }
101     }
102     /// <summary>
103     ///这是 类，有好多方法
104     /// </summary>
105     public class TestDel
106     {
107         #region 普通方法
108         /// <summary>
109         /// 静态方法
110         /// </summary>
111         public static void MyStaticMethod()
112         {
113             Console.WriteLine("My Static Method");
114         }
115         /// <summary>
116         /// 输出 mymethod
117         /// </summary>
118         public void MyMethod()
119         {
120             Console.WriteLine("MyMethod");
121         }
122         public void MyMethod2()
123         {
124             Console.WriteLine("My Method 22222222222");
125         }
126         /// <summary>
127         /// 静态函数
128         /// </summary>
129         public static void MyMethod3()
130         {
131             Console.WriteLine("My Method 3333333333333");
132         }
133         /// <summary>
134         /// 返回两个数的和
135         /// </summary>
136         /// <param name="num1"></param>
137         /// <param name="num2"></param>
138         public void MyMethod(int num1, int num2)
139         {
140             Console.WriteLine(num1 + num2);
141         }
142         /// <summary>
143         /// 字符串变成大写
144         /// </summary>
145         /// <param name="s"></param>
146         /// <returns></returns>
147         public string MyMethod(string s)
148         {
149             return s.ToUpper();
150         }
151         #endregion
152 
153         /// <summary>
154         /// 委托作为方法参数
155         /// </summary>
156         /// <param name="s"></param>
157         /// <param name="del3"></param>
158         public static void MyParamMethod(string s, MyDelStrUp del3)
159         {
160             Console.WriteLine(del3(s));
161         }
162 
163         /// <summary>
164         /// 委托作为返回值
165         /// </summary>
166         /// <param name="s"></param>
167         /// <returns></returns>
168         public MyDelStrUp MyReturnMethod()
169         {
170             ///返回符合委托规范的方法
171             return MyMethod;
172         }
173     }
174 
175    // 委托作为参数
176 
177   public class MyParamDelegateTest
178     {
179         BookDB bookDB = new BookDB();
180         public void AddBooks()
181         {          
182             bookDB.AddBook(new Book() { BookID=1,BookName="C#",Price=123,IsPaperbook=true });
183             bookDB.AddBook(new Book() { BookID = 1, BookName = "C#", Price = 123, IsPaperbook = false });
184             bookDB.AddBook(new Book() { BookID = 2, BookName = "ASP.Net", Price = 12, IsPaperbook = true });
185             bookDB.AddBook(new Book() { BookID = 1, BookName = "ADO", Price = 23, IsPaperbook = false });
186         }
187         /// <summary>
188         /// 用来实例化委托
189         /// </summary>
190         /// <param name="b"></param>
191         public void TestProcessBook(Book b)
192         {
193             if (b.IsPaperbook)
194             {
195                 Console.WriteLine(b.BookName);
196             }
197         }
198         double total = 0;
199         public void TotalPrice(Book b)
200         {
201             total += b.Price;
202         }
203         public void MyTest()
204         {
205            
206             //ProcessBook p=TestProcessBook;
207             //ProcessBook p1=TotalPrice;
208             //ProcessBook p2=p+p1;
209             //把方法名做为参数进行传递
210             bookDB.PrintBook(TestProcessBook);
211             bookDB.PrintBook(TotalPrice);
212             Console.WriteLine(total);
213         }
214 
215 
216     }
217     /// <summary>
218     /// 委托
219     /// </summary>
220     /// <param name="b"></param>
221     public delegate void ProcessBook(Book b);
222 
223     public class BookDB
224     {
225         public List<Book> books = new List<Book>();
226         public void AddBook(Book b)
227         {
228             books.Add(b);
229         }
230         /// <summary>
231         /// 委托做参数
232         /// </summary>
233         /// <param name="process">委托</param>
234         public void PrintBook(ProcessBook process)
235         {
236             foreach (var book in books)
237             {
238                 //这里进行委托传进来的函数 操作book
239                 process(book);
240             }            
241         }
242     }
243 
244     public class Book
245     {
246         public int BookID { get; set; }
247         public string BookName { get; set; }
248         public double Price { get; set; }
249         public bool IsPaperbook { get; set; }
250     }
251 
252   //  委托作为返回值
253 
254    public delegate int MyReturnDelegate(int num1, int num2);
255 
256     public class MyReturnDelegateTest
257     {
258         public void MyTest()
259         {
260             MyCalcuate myCalcuate = new MyCalcuate();
261             do
262             {
263                 Console.WriteLine("请输入符号进行以计算( + - * /)");
264                 string oper = Console.ReadLine();
265                 Console.WriteLine("请输入操作数1");
266                 string num1 = Console.ReadLine();
267 
268                 Console.WriteLine("请输入操作数2");
269                 string num2 = Console.ReadLine();
270 
271                 MyReturnDelegate myReturn = myCalcuate.Calcuate(oper);
272                 int result = myReturn(int.Parse(num1), int.Parse(num2));
273                 Console.WriteLine(
274                     string.Format("{0}{1}{2}={3}", num1,oper,num2, result));
275 
276                 Console.WriteLine("您还要继续吗?Y/N");
277                 //string continueFlag = Console.ReadLine();
278                 //if (continueFlag.ToUpper() == "N") break;
279 
280             } while (Console.ReadLine().ToUpper()!="N");
281         }
282     }
283 
284     public class MyCalcuate
285     {
286         public MyReturnDelegate Calcuate(string oper)
287         {
288             MyReturnDelegate myReturn = null;
289             switch (oper)
290             {
291                 case "+":
292                     myReturn = delegate(int num1, int num2) { return num1 + num2; };
293                     break;
294                 case "-":
295                     myReturn = delegate(int num1, int num2) { return num1 - num2; };
296                     break;
297                 case "*":
298                     myReturn = delegate(int num1, int num2) { return num1 * num2; };
299                     break;
300                 case "/":
301                     myReturn = delegate(int num1, int num2) { return num1 / num2; };
302                     break;
303                 default:
304                     break;
305             }
306             return myReturn;
307         }
308     }
309 }