gistfile1.cs

using System.Dynamic;
using System.Linq;
using System.Reflection;
using Microsoft.CSharp.RuntimeBinder;
using NUnit.Framework;
using SharpTestsEx;

namespace SampleMixin
{
	public class Foo
	{
		public string FooProperty { get; set; }
	}

	public class Bar
	{
		public string BarProperty { get; set; }
	}

	[TestFixture]
	public class SampleTests
	{
		[Test]
		public void CanGetProperty()
		{
			var foo = new Foo {FooProperty = "Test"};
			var bar = new Bar {BarProperty = "Other"};

			dynamic mixin = new Mixin(foo, bar);

			Assert.AreEqual("Test", mixin.FooProperty);
			Assert.AreEqual("Other", mixin.BarProperty);
		}

		[Test]
		public void CanSetProperty()
		{
			var foo = new Foo {FooProperty = "Test"};
			var bar = new Bar {BarProperty = "Other"};

			dynamic mixin = new Mixin(foo, bar);
			mixin.FooProperty = "Alll";

			foo.FooProperty.Should().Be.EqualTo("Alll");
		}

		[Test]
		public void WhenGettingAPropertyThatDoesNotExistsThenThrowRuntimeBinderException()
		{
			var foo = new Foo {FooProperty = "Test"};
			var bar = new Bar {BarProperty = "Other"};

			dynamic mixin = new Mixin(foo, bar);

			Assert.Throws<RuntimeBinderException>(() => { dynamic r = mixin.InvalidProperty; });
		}

		[Test]
		public void WhenSettingAPropertyThatDoesNotExistsThenThrowRuntimeBinderException()
		{
			var foo = new Foo {FooProperty = "Test"};
			var bar = new Bar {BarProperty = "Other"};

			dynamic mixin = new Mixin(foo, bar);

			Assert.Throws<RuntimeBinderException>(() => { mixin.InvalidProperty = "Jjjs"; });
		}
	}

	public class Mixin : DynamicObject
	{
		private readonly object[] mixeds;

		public Mixin(params object[] mixeds)
		{
			this.mixeds = mixeds;
		}

		public override bool TryGetMember(GetMemberBinder binder, out object result)
		{
			PropertyObjectPair pair = GetPropertyObjectPair(binder.Name);
			if (pair == null)
			{
				result = null;
				return false;
			}
			object value = pair.Property.GetValue(pair.Object, null);
			result = value;
			return true;
		}

		public override bool TrySetMember(SetMemberBinder binder, object value)
		{
			PropertyObjectPair pair = GetPropertyObjectPair(binder.Name);
			if (pair == null) return false;
			pair.Property.SetValue(pair.Object, value, null);
			return true;
		}

		private PropertyObjectPair GetPropertyObjectPair(string binderName)
		{
			return mixeds.Select(m => new PropertyObjectPair
			                          	{
			                          		Property = m.GetType().GetProperty(binderName),
			                          		Object = m
			                          	})
				.FirstOrDefault(p => p.Property != null);
		}

		#region Nested type: PropertyObjectPair

		public class PropertyObjectPair
		{
			public object Object { get; set; }
			public PropertyInfo Property { get; set; }
		}

		#endregion
	}
}