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.

      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:

     public class DelegateObj
     {
         private MyDelegate _delegate;  
 
         public MyDelegate CallMethod
         {
             get { return _delegate; }
         }
         private DelegateObj(MyDelegate D)
         {
             _delegate = D;
         }
         /// <summary>
         /// 构造委托对象，让它看起来有点javascript定义的味道.
         /// </summary>
         /// <param name="D"></param>
         /// <returns></returns>
         public static DelegateObj Function(MyDelegate D)
         {
             return new DelegateObj(D);
         }
     }  

3) 定义一个动态对象:

     public class DynObj : DynamicObject
     {
         //保存对象动态定义的属性值
         private Dictionary<string, object> _values;
         public DynObj()
         {
             _values = new Dictionary<string, object>();
         }
         /// <summary>
         /// 获取属性值
         /// </summary>
         /// <param name="propertyName"></param>
         /// <returns></returns>
         public object GetPropertyValue(string propertyName)
         {
             if (_values.ContainsKey(propertyName) == true)
             {
                 return _values[propertyName];
             }
             return null;
         }
         /// <summary>
         /// 设置属性值
         /// </summary>
         /// <param name="propertyName"></param>
         /// <param name="value"></param>
         public void SetPropertyValue(string propertyName,object value)
         {
             if (_values.ContainsKey(propertyName) == true)
             {
                 _values[propertyName] = value;
             }
             else
             {
                 _values.Add(propertyName, value);
             }
         }
         /// <summary>
         /// 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
         /// </summary>
         /// <param name="binder"></param>
         /// <param name="result"></param>
         /// <returns></returns>
         public override bool TryGetMember(GetMemberBinder binder, out object result)
         {
             result = GetPropertyValue(binder.Name);
             return result == null ? false : true;
         }
         /// <summary>
         /// 实现动态对象属性值设置的方法。
         /// </summary>
         /// <param name="binder"></param>
         /// <param name="value"></param>
         /// <returns></returns>
         public override bool TrySetMember(SetMemberBinder binder, object value)
         {
             SetPropertyValue(binder.Name, value);
             return true;
         }
         /// <summary>
         /// 动态对象动态方法调用时执行的实际代码
         /// </summary>
         /// <param name="binder"></param>
         /// <param name="args"></param>
         /// <param name="result"></param>
         /// <returns></returns>
         public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
         {
             var theDelegateObj = GetPropertyValue(binder.Name) as DelegateObj;
             if (theDelegateObj == null || theDelegateObj.CallMethod == null)
             {
                 result = null;
                 return false;
             }
             result = theDelegateObj.CallMethod(this,args);
             return true;
         }
         public override bool TryInvoke(InvokeBinder binder, object[] args, out object result)
         {
             return base.TryInvoke(binder, args, out result);
         }
     }  

测试代码：

            dynamic theObj = new DynObj();
            theObj.aaa = "this is a test";//动态属性
            //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.
            theObj.show = DelegateObj.Function((s, pms) =>
            {
                if (pms != null && pms.Length > )
                {
                    MessageBox.Show(pms[].ToString() + ":" + s.aaa);
                }
                else
                {
                    MessageBox.Show(s.aaa);
                }
                return null;
            }
            );
            theObj.show("hello");