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  1. using System;
  2. using System.Collections.Generic;
  3. using System.Dynamic;
  4. using System.Linq;
  5. using System.Linq.Expressions;
  6. using System.Reflection;
  7.  
  8. namespace ConsoleTest
  9. {
  10.     class Program
  11.     {
  12.         static void Main(string[] args)
  13.         {
  14.             var a = new A { Prop1 = 0, Prop2 = "1", Prop3 = 2.0 };
  15.             Console.WriteLine(a);
  16.             dynamic d = new Decorator<A>(a);
  17.             d.Prop1 = 3;
  18.             d.Prop2 = "4";
  19.             d.Prop3 = 5.0;
  20.             Console.WriteLine(a);
  21.             Console.ReadKey();
  22.         }
  23.     }
  24.  
  25.     class A
  26.     {
  27.         public int Prop1 { get; set; }
  28.         public string Prop2 { get; set; }
  29.         public double Prop3 { get; set; }
  30.         public override string ToString() => $"Prop1={Prop1}, Prop1={Prop2}, Prop1={Prop3}";
  31.     }
  32.  
  33.     class Decorator<T> : DynamicObject
  34.     {
  35.         private static readonly IReadOnlyDictionary<string, Action<T, object>> props;
  36.  
  37.         static Decorator()
  38.         {
  39.             props = typeof(T).GetProperties().ToDictionary(pi => pi.Name, CreateSetter);
  40.         }
  41.  
  42.         private static Action<T, object> CreateSetter(PropertyInfo pi)
  43.         {
  44.             var obj = Expression.Parameter(typeof(T), "t");
  45.             var val = Expression.Parameter(typeof(object), "o");
  46.             var prop = Expression.Property(obj, pi);
  47.             var set = Expression.Assign(prop, Expression.Convert(val, pi.PropertyType));
  48.             var lambda = Expression.Lambda<Action<T, object>>(set, obj, val);
  49.             return lambda.Compile();
  50.         }
  51.  
  52.         private readonly T obj;
  53.  
  54.         public Decorator(T obj)
  55.         {
  56.             this.obj = obj;
  57.         }
  58.  
  59.         public override bool TrySetMember(SetMemberBinder binder, object value)
  60.         {
  61.             Action<T, object> setter;
  62.             if (!props.TryGetValue(binder.Name, out setter)) return false;
  63.             Console.WriteLine($"{binder.Name} = {value}");
  64.             setter(obj, value);
  65.             return true;
  66.         }
  67.     }
  68. }
Success #stdin #stdout 0.16s 141952KB
comments (?)
stdin 
Standard input is empty
stdout 
Prop1=0, Prop1=1, Prop1=2
Prop1 = 3
Prop2 = 4
Prop3 = 5
Prop1=3, Prop1=4, Prop1=5
https://ideone.com/jIgQu0
language:
C# (gmcs 5.20.1)
created:
7 years ago
visibility:
public

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