c#泛型(包括泛型抽象类的继承)

1.泛型和泛型强制转换

 using System;
 using System.Collections.Generic;
 using System.Text;
 
 namespace VS2005Demo2
 6{
 7
 8    C# 编译器只允许将泛型参数隐式强制转换到 Object 或约束指定的类型#region  C# 编译器只允许将泛型参数隐式强制转换到 Object 或约束指定的类型
 9    public interface ISomeInterface
10    { }
11    class BaseClass
12    { }
13    class MyClass<T> where T : BaseClass, ISomeInterface
14    {
15        void SomeMethod(T t)
16        {
17            ISomeInterface obj1 = t;
18            BaseClass obj2 = t;
19            object obj3 = t;
20        }
21    }
22    #endregion
23
24    编译器允许您将泛型参数显式强制转换到其他任何接口，但不能将其转换到类#region 编译器允许您将泛型参数显式强制转换到其他任何接口，但不能将其转换到类
25    class SomeClass
26    { }
27    //class MyClass1<T>
28    //{
29    //    void SomeMethod(T t)
30    //    {
31    //        ISomeInterface obj1 = (ISomeInterface)t;  //Compiles
32    //        SomeClass obj2 = (SomeClass)t;           //Does not compile
33    //    }
34    //}
35    #endregion
36
37
38    使用临时的 Object 变量，将泛型参数强制转换到其他任何类型#region 使用临时的 Object 变量，将泛型参数强制转换到其他任何类型
39    class MyClass2<T>
40    {
41        void SomeMethod(T t)
42        {
43            object temp = t;
44            SomeClass obj = (SomeClass)temp;
45        }
46    }
47    #endregion
48
49    使用is和as运算符#region 使用is和as运算符
50    public class MyClass3<T>
51    {
52        public void SomeMethod(T t)
53        {
54            if (t is int) { }
55            if (t is LinkedList<int, string>) { }
56            string str = t as string;
57            if (str != null) { }
58            LinkedList<int, string> list = t as LinkedList<int, string>;
59            if (list != null) { }
60        }
61    }
62    #endregion
63
64}
65

2.继承和泛型

  1using System;
  2using System.Collections.Generic;
  3using System.Text;
  4
  5namespace VS2005Demo2
  6{
  7    继承和泛型#region 继承和泛型
  8    public class BaseClass<T>
  9    { }
 10    public class SubClass : BaseClass<int>
 11    { }
 12
 13
 14    public class SubClass1<R> : BaseClass<R>
 15    { }
 16    #endregion
 17
 18    继承约束#region 继承约束
 19    public class BaseClass1<T> where T : ISomeInterface
 20    { }
 21    public class SubClass2<T> : BaseClass1<T> where T : ISomeInterface
 22    { }
 23
 24    //构造函数约束
 25    public class BaseClass3<T> where T : new()
 26    {
 27        public T SomeMethod()
 28        {
 29            return new T();
 30        }
 31    }
 32    public class SubClass3<T> : BaseClass3<T> where T : new()
 33    { }
 34
 35    #endregion
 36
 37    虚拟方法#region 虚拟方法
 38    public class BaseClass4<T>
 39    {
 40        public virtual T SomeMethod()
 41        {
 42            return default(T);
 43        }
 44    }
 45    public class SubClass4 : BaseClass4<int>
 46    {
 47        public override int SomeMethod()
 48        {
 49            return 0;
 50        }
 51    }
 52
 53    public class SubClass5<T> : BaseClass4<T>
 54    {
 55        public override T SomeMethod()
 56        {
 57            return default(T);
 58        }
 59    }
 60
 61    #endregion
 62
 63    接口、抽象类继承#region 接口、抽象类继承
 64    public interface ISomeInterface6<T>
 65    {
 66        T SomeMethod(T t);
 67    }
 68    public abstract class BaseClass6<T>
 69    {
 70        public abstract T SomeMethod(T t);
 71    }
 72    public class SubClass6<T> : BaseClass6<T>,ISomeInterface6<T>
 73    {
 74        public override T SomeMethod(T t)
 75        { return default(T); }
 76    }
 77    #endregion
 78
 79    泛型抽象方法和泛型接口#region 泛型抽象方法和泛型接口
 80    //public class Calculator<T>
 81    //{
 82    //    public T Add(T arg1, T arg2)
 83    //    {
 84    //        return arg1 + arg2;//Does not compile 
 85    //    }
 86    //    //Rest of the methods 
 87    //}
 88
 89    public abstract class BaseCalculator<T>
 90    {
 91        public abstract T Add(T arg1, T arg2);
 92        //public abstract T Subtract(T arg1, T arg2);
 93        //public abstract T Divide(T arg1, T arg2);
 94        //public abstract T Multiply(T arg1, T arg2);
 95    }
 96    public class MyCalculator : BaseCalculator<int>
 97    {
 98        public override int Add(int arg1, int arg2)
 99        {
100            return arg1 + arg2;
101        }
102        //Rest of the methods 
103    }
104
105    public interface ICalculator<T>
106    {
107        T Add(T arg1, T arg2);
108        //Rest of the methods 
109    }
110    public class MyCalculator1 : ICalculator<int>
111    {
112        public int Add(int arg1, int arg2)
113        {
114            return arg1 + arg2;
115        }
116        //Rest of the methods 
117    }
118    #endregion
119
120}
121

3.泛型方法

  1using System;
  2using System.Collections.Generic;
  3using System.Text;
  4
  5namespace VS2005Demo2
  6{
  7
  8    泛型方法#region 泛型方法
  9    public class MyClass
 10    {
 11        public void MyMethod<T>(T t)
 12        { }
 13    }
 14
 15    public class Class3
 16    {
 17        public void Test()
 18        {
 19            MyClass obj = new MyClass();
 20            obj.MyMethod<int>(3);
 21
 22            obj.MyMethod(3);
 23        }
 24    }
 25    #endregion
 26
 27    编译器无法只根据返回值的类型推断出类型#region 编译器无法只根据返回值的类型推断出类型
 28    public class MyClass1
 29    {
 30        public T MyMethod<T>()
 31        { return default(T); }
 32    }
 33
 34    public class Class31
 35    {
 36        public void Test()
 37        {
 38
 39            MyClass1 obj = new MyClass1();
 40            int number = obj.MyMethod<int>();
 41        }
 42    }
 43    #endregion
 44
 45    泛型方法约束#region 泛型方法约束
 46    public class Class32
 47    {
 48        public T MyMethod<T>(T t) where T : IComparable<T>
 49        { return default(T); }
 50    }
 51    #endregion
 52
 53    泛型虚拟方法#region 泛型虚拟方法
 54    public class BaseClass33
 55    {
 56        public virtual void SomeMethod<T>(T t)
 57        { }
 58    }
 59    public class SubClass33 : BaseClass33
 60    {
 61        public override void SomeMethod<T>(T t)
 62        {
 63            base.SomeMethod<T>(t);
 64        }
 65    }
 66
 67    public class BaseClass34
 68    {
 69        public virtual void SomeMethod<T>(T t) where T : new()
 70        { }
 71    }
 72    public class SubClass34 : BaseClass34
 73    {
 74        public override void SomeMethod<T>(T t)// where T : IComparable<T>
 75        { }
 76    }
 77
 78    public class BaseClass35
 79    {
 80        public virtual void SomeMethod<T>(T t)
 81        { }
 82    }
 83    public class SubClass35 : BaseClass35
 84    {
 85        public override void SomeMethod<T>(T t)
 86        {
 87            base.SomeMethod<T>(t);
 88            base.SomeMethod(t);
 89        }
 90    }
 91    #endregion
 92
 93    泛型静态方法#region 泛型静态方法
 94    public class MyClass36<T>
 95    {
 96        public static T SomeMethod(T t)
 97        { return default(T); }
 98    }
 99
100    public class Class36
101    {
102        public void Test()
103        {
104            int number = MyClass36<int>.SomeMethod(3);
105        }
106    }
107
108    public class MyClass37<T>
109    {
110        public static T SomeMethod<X>(T t, X x)
111        { return default(T); }
112    }
113    public class Class37
114    {
115        public void Test()
116        {
117            int number = MyClass37<int>.SomeMethod<string>(3, "AAA");
118            int number1 = MyClass37<int>.SomeMethod(3, "AAA");
119        }
120    }
121
122    public class MyClass38
123    {
124        public static T SomeMethod<T>(T t) where T : IComparable<T>
125        {  return default(T); }
126    }
127
128    #endregion
129}
130

4.泛型委托

 1using System;
 2using System.Collections.Generic;
 3using System.Text;
 4
 5namespace VS2005Demo2
 6{
 7    泛型委托#region 泛型委托
 8    public class MyClass40<T>
 9    {
10        public delegate void GenericDelegate(T t);
11        public void SomeMethod(T t)
12        { }
13    }
14
15    public class MyClassTest40
16    {
17        public void Tests()
18        {
19            MyClass40<int> obj = new MyClass40<int>();
20            MyClass40<int>.GenericDelegate del;
21
22            del = new MyClass40<int>.GenericDelegate(obj.SomeMethod);
23            del(3);
24
25            //委托推理
26            del = obj.SomeMethod;
27
28        }
29    }
30    #endregion
31
32    委托泛型参数#region 委托泛型参数
33    public class MyClass41<T>
34    {
35        public delegate void GenericDelegate<X>(T t, X x);
36    }
37
38    //外部委托
39    public delegate void GenericDelegate<T>(T t);
40
41    public class MyClass42
42    {
43        public void SomeMethod(int number)
44        { }
45    }
46
47    public class MyClassTest42
48    {
49        public void Test()
50        {
51            MyClass42 obj = new MyClass42();
52            GenericDelegate<int> del;
53            //del = new GenericDelegate<int>(obj.SomeMethod);
54
55            del = obj.SomeMethod;
56            del(3);
57
58        }
59    }
60
61    #endregion
62
63    委托泛型参数#region 委托泛型参数
64    public delegate void MyDelegate<T>(T t) where T : IComparable<T>;
65    #endregion
66
67    事件#region 事件
68
69    public delegate void GenericEventHandler<S, A>(S sender, A args);
70    
71    public class MyPublisher
72    {
73        public event GenericEventHandler<MyPublisher, EventArgs> MyEvent;
74        public void FireEvent()
75        {
76            MyEvent(this, EventArgs.Empty);
77        }
78    }
79
80    public class MySubscriber<A> //Optional: can be a specific type
81    {
82        public void SomeMethod(MyPublisher sender, A args)
83        { }
84    }
85    public class MyClassTest43
86    {
87        public void Test()
88        {
89            MyPublisher publisher = new MyPublisher();
90            MySubscriber<EventArgs> subscriber = new MySubscriber<EventArgs>();
91            publisher.MyEvent += subscriber.SomeMethod;
92        }
93    }
94    #endregion
95}