C#:如何在运行时向对象添加属性？

using System;
using System.Reflection;
using System.Reflection.Emit;

public class DynamicProperty
{
    public static void Main()
    {
        // 创建一个动态类型
        AssemblyBuilder assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("DynamicAssembly"), AssemblyBuilderAccess.Run);
        ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule("DynamicModule");
        TypeBuilder typeBuilder = moduleBuilder.DefineType("DynamicType", TypeAttributes.Public);

        // 创建一个动态属性
        FieldBuilder fieldBuilder = typeBuilder.DefineField("DynamicField", typeof(string), FieldAttributes.Public);
        PropertyBuilder propertyBuilder = typeBuilder.DefineProperty("DynamicProperty", PropertyAttributes.None, typeof(string), Type.EmptyTypes);
        MethodBuilder getMethodBuilder = typeBuilder.DefineMethod("GetDynamicProperty", MethodAttributes.Public | MethodAttributes.SpecialName, typeof(string), Type.EmptyTypes);
        ILGenerator getIlGenerator = getMethodBuilder.GetILGenerator();
        getIlGenerator.Emit(OpCodes.Ldarg_0);
        getIlGenerator.Emit(OpCodes.Ldfld, fieldBuilder);
        getIlGenerator.Emit(OpCodes.Ret);

        MethodBuilder setMethodBuilder = typeBuilder.DefineMethod("SetDynamicProperty", MethodAttributes.Public | MethodAttributes.SpecialName, typeof(void), new Type[] { typeof(string) });
        ILGenerator setIlGenerator = setMethodBuilder.GetILGenerator();
        setIlGenerator.Emit(OpCodes.Ldarg_0);
        setIlGenerator.Emit(OpCodes.Ldarg_1);
        setIlGenerator.Emit(OpCodes.Stfld, fieldBuilder);
        setIlGenerator.Emit(OpCodes.Ret);

        propertyBuilder.SetGetMethod(getMethodBuilder);
        propertyBuilder.SetSetMethod(setMethodBuilder);

        // 创建动态类型的实例
        Type dynamicType = typeBuilder.CreateType();
        object dynamicInstance = Activator.CreateInstance(dynamicType);

        // 使用动态属性
        dynamicType.GetProperty("DynamicProperty").SetValue(dynamicInstance, "Hello, world!");
        string value = (string)dynamicType.GetProperty("DynamicProperty").GetValue(dynamicInstance);
        Console.WriteLine(value);
    }
}