C#动态对象(dynamic)示例(实现方法和属性的动态)

C#的动态对象的属性实现比较简单,如果要实现动态语言那种动态方法就比较困难,因为对于dynamic对象,扩展方法,匿名方法都是不能用直接的,这里还是利用对象和委托来模拟这种动态方法的实现,看起来有点JavaScript的对象味道:

1)定义一个委托,参数个数可变,参数都是object类型:这里的委托多有个dynamic参数,代表调用这个委托的动态对象本身.

1      public delegate object MyDelegate(dynamic Sender, params object[] PMs);

2)定义一个委托转载对象,因为dynamic对象不能直接用匿名方法,这里用对象去承载:

 1     public class DelegateObj  
 2     {  
 3         private MyDelegate _delegate;  
 4   
 5         public MyDelegate CallMethod  
 6         {  
 7             get { return _delegate; }  
 8         }  
 9         private DelegateObj(MyDelegate D)  
10         {  
11             _delegate = D;  
12         }  
13         /// <summary>  
14         /// 构造委托对象，让它看起来有点javascript定义的味道.  
15         /// </summary>  
16         /// <param name="D"></param>  
17         /// <returns></returns>  
18         public static DelegateObj Function(MyDelegate D)  
19         {  
20             return new DelegateObj(D);  
21         }  
22     }

3) 定义一个动态对象:

 1     public class DynObj : DynamicObject  
 2     {  
 3         //保存对象动态定义的属性值  
 4         private Dictionary<string, object> _values;  
 5         public DynObj()  
 6         {  
 7             _values = new Dictionary<string, object>();  
 8         }  
 9         /// <summary>  
10         /// 获取属性值  
11         /// </summary>  
12         /// <param name="propertyName"></param>  
13         /// <returns></returns>  
14         public object GetPropertyValue(string propertyName)  
15         {  
16             if (_values.ContainsKey(propertyName) == true)  
17             {  
18                 return _values[propertyName];  
19             }  
20             return null;  
21         }  
22         /// <summary>  
23         /// 设置属性值  
24         /// </summary>  
25         /// <param name="propertyName"></param>  
26         /// <param name="value"></param>  
27         public void SetPropertyValue(string propertyName,object value)  
28         {  
29             if (_values.ContainsKey(propertyName) == true)  
30             {  
31                 _values[propertyName] = value;  
32             }  
33             else  
34             {  
35                 _values.Add(propertyName, value);  
36             }  
37         }  
38         /// <summary>  
39         /// 实现动态对象属性成员访问的方法，得到返回指定属性的值  
40         /// </summary>  
41         /// <param name="binder"></param>  
42         /// <param name="result"></param>  
43         /// <returns></returns>  
44         public override bool TryGetMember(GetMemberBinder binder, out object result)  
45         {  
46             result = GetPropertyValue(binder.Name);  
47             return result == null ? false : true;  
48         }  
49         /// <summary>  
50         /// 实现动态对象属性值设置的方法。  
51         /// </summary>  
52         /// <param name="binder"></param>  
53         /// <param name="value"></param>  
54         /// <returns></returns>  
55         public override bool TrySetMember(SetMemberBinder binder, object value)  
56         {  
57             SetPropertyValue(binder.Name, value);  
58             return true;  
59         }  
60         /// <summary>  
61         /// 动态对象动态方法调用时执行的实际代码  
62         /// </summary>  
63         /// <param name="binder"></param>  
64         /// <param name="args"></param>  
65         /// <param name="result"></param>  
66         /// <returns></returns>  
67         public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)  
68         {  
69             var theDelegateObj = GetPropertyValue(binder.Name) as DelegateObj;  
70             if (theDelegateObj == null || theDelegateObj.CallMethod == null)  
71             {  
72                 result = null;  
73                 return false;  
74             }  
75             result = theDelegateObj.CallMethod(this,args);  
76             return true;  
77         }  
78         public override bool TryInvoke(InvokeBinder binder, object[] args, out object result)  
79         {  
80             return base.TryInvoke(binder, args, out result);  
81         }  
82     }

测试代码：

 1            dynamic theObj = new DynObj();  
 2            theObj.aaa = "this is a test";//动态属性  
 3            //动态方法，这里不能没法定义参数，调用的时候可以是任意多参数，具体参数类型和含义就只能自己去小心处理了.  
 4            theObj.show = DelegateObj.Function((s, pms) =>  
 5            {  
 6                if (pms != null && pms.Length > 0)  
 7                {  
 8                    MessageBox.Show(pms[0].ToString() + ":" + s.aaa);  
 9                }  
10                else  
11                {  
12                    MessageBox.Show(s.aaa);  
13                }  
14                return null;  
15            }  
16            );  
17            theObj.show("hello");